Yeah, don't get me wrong, games have heavily evolved in many ways. Music, Gameplay, Graphical output, Unique Designs. To say the newer Zelda games aren't better than the old ones isn't exactly true. But to say they're the ultimate improvement? Nope. Let's run down a history of the all the regular Zelda games, not counting CD-i ones in this equation.
The Legend of Zelda - This is one of the most unique Action/Adventure games that you can find. Not many games used the overhead view, although it did bring us a lot of similar games in the same genre. No, it wasn't the first kind of game to do this, but it sure was well-made. One of the things that made this game unique was the catchy music, secrets, and the items. You will use 90% of the items multiple times in multiple areas. About the only items that were rarely used were the Power Bracelets and the Raft. But that's okay. They had their uses, even if it was in the Overworld and not the Dungeons. The monster designs, despite being pretty simple because of what they had to work with, were pretty damn unique. Sure, they were based off of many classic ideas, but with new names. Mummies, Skeletons, Octupi, Orks, and so on. That was fine. The last most important thing is that while you needed to get some of the Dungeons items in one particular order, you could finish every bit of the game at your own pace. But let's move on.
Zelda II: The Adventure of Link - This is the only game that could be consider an rpg, because it had the makings of one specifically. Albeit, it was a side-scrolling Action RPG, but that was fine. Like the first game, the items were nearly all used multiple times. Plus, it was the only one to have unique spells. Sure, most Zelda games incomporated Magic in some way, but none had your own specific spell list, atleast till a slight variation in Ocarina of Time. What made this game even more interesting is that it was much more challenging. The enemies hit hard, the A.I. wasn't random, but good. That's something that doesn't happen often in games. At most, it had a few enemies that re-spawned in an annoying way. But other than that, a cult classic that will kick your ass. Also, this is the first appearnce of the Downthrust and Upthrust.
The Legend of Zelda: A Link to the Past - This literally re-defined the series in a new way. While the gameplay was like the original, the graphics were improved, and it had far too many items that you may never need. The bosses were very challenging, and there were even more secrets to be found. Sure, the game had a bit of fake difficulty with invisible floors, and some semi-cheap monsters. But what's the fun of a game if it's too easy? It also kept magic, but made them into items, which is a very common thing in many of the games now.
The Legend of Zelda: Link's Awakening - This is the first game to really start developing the characters. While the second and third game had a little, it never went indepth besides catering to the current storyline. It was exposition, not actual character development.(in my opinion) This game also introduced Marin and Tarin, who would later on become Malon and Talon in later series. Now, the gameplay itself is just like A Link to the Past, due to being based off of the same starting game. The key differences between the two were the number of dungeons, the lack of actual magic, and the less items available. On the other hand, you constantly re-used almost every item a huge ammount of times, making them all worthwhile. It can also kick your ass with its challenge. But none of it is badly done, save maybe the final main dungeon.
The Legend of Zelda: Ocarina of Time - This is the first 3D Action-Adventure Zelda game. Was it good? Of course. They did a very excellent job in trying 3D. However, it suffered from fairly flat characters, a somewhat cliche storyline, and many useless items. But it still kept the Zelda theme going strong, and was very fun to play. It also got remade into a GameCube game called Master Quest(Outside of Japan). This game also introduced your mighty steed, Epona, named after the Horse Goddess of Travel. Likewise, it started the trend of the Fire/Ice/Light Arrows that appeared in later games.
The Legend of Zelda: Majora's Mask - While it continued off of ones of the storyline endings of Ocarina of Time, it re-used the character models. On the other hand, it gaves them tons of character development, and tried many new ideas. The major appeal is the Mask system, which allow you to Transform or have special powers. Some were very one-use, while others were overused as well. That's the problem with tons of items. Anyway, it brought back just about every item from Ocarina of Time, and gave the game a new plot dealing with Time Travel. You got 3 days to do stuff. The game is filled with Side Quests for hearts, helping people, and to gain cool items or abilities. The time frame may make it very difficult for some, however.
The Legend of Zelda: Oracle of Ages/Seasons - These are the first two(and only two) games that allowed you to connect to eachother(but not the same copy) for various secrets. Both game's plots were somewhat similar, but had a lot of unique ideas. Seasons was originally a remake of the first Zelda game and it shows. From the same first 8 bosses, to the items and similar Overworld. Your goal was to change the seasons themself to get to areas to save the day. Ages, on the other hand, used Time Travel once more to go back and forth to find areas, secrets, and to affect the actual areas themself. While that particular part is recycled from Ocarina of Time, it did it much better, by making it the focus, and much more important to the storyline than just being a simple Plot Device. Both games had recycled versions of classic enemies, and new items called Rings, which you could equip for various effects. You could make your Sword deal more damage, make an item last longer as well. The other items introduced were Seeds, which could affect gameplay is various ways. One could make you go faster, while another leads enemies away. And so on. While not every item in both games were useful, it really did try to be unique from the other series.
The Legend of Zelda: The Wind Waker - Let's start off with the first major change. It uses Cel-Shaded graphics, which gained a giant controversy over being called "kiddy". On the other hand, the game was far from it. It's storyline was more than dark enough, with a final boss that helped kidnapped characters, for starters. But to say the entire storyline would detract from my point, and would spoil it. Long story short, it's the same major bad guy throughout the series, but all new with many twists in his personality. The items were indeed recycled a bit, but tons of new items were used. For the first time, you didn't use an Instrument in the series. Instead, you had a Conducting Baton.(I may be incorrect on this term, feedback here please) Regardless, you still played lots of music in this game, as per the usual. Another item introduced was the all-mighty Deku Leaf, which not only gave you flight, but could create a gust of wind to slam enemies away, or work with puzzles. By far the greatest point to this game, is how extremely well-developed the characters were. Nobody was flat, not even the least important NPC. Everybody was useful and worth talking to.
The Legend of Zelda: A Link to the Past: Four Swords - First, it's a remake of the named game. Second, it had many changes, some harder enemies, and an all new side quest that you could play in multiplayer. This introduced true multiplayer to the Zelda series. There's not much more to say on it, other than improved gameplay and some new challenges. Likewise, the Four Swords part required multiplayer, however.
The Legend of Zelda: Four Swords Adventures - This is another unique game in the series. It introduced an item or two that would later on get re-used in a similar game. This is also the second game to use Cel-Shaded graphics, or atleast the titular Toon Link. Unlike most Zelda games, this allows you to have multiplayer with tons of players. However, this wasn't the rule either. You could play it alone, or with friends. Notably, this continued from "Four Swords" with a similar major enemy, and similar gameplay. You'll find that it is much more difficult, and the bosses and challenges are even greater than before.
The Legend of Zelda: Twilight Princess - While this game was indeed good, and introduced many new items, it also is where the series started to go downhill overall. First, it was created as a GameCube game, and ported to the Wii. This denied us a true Wii Zelda game, but that's just nitpicky. Remember how I said up there that the items were really unique and used often? Not so much in this game. Most items will rarely be used outside of their original dungeon, and some are entirely useless as is. No matter how awesome they are, they're not going to be used much. The Ball & Chain is one of the coolest items in the game, but entirely slow and most enemies are much faster. Likewise, it doesn't affect anything easier to use items don't affect better. Another thing they did was make the Bow the most overused Item in the game. The problems is that you no longer had the Fire/Ice/Light Arrows. Sure, you could make the Bomb Arrow, which was introduced in Link's Awakening, but that was it. The mini-games weren't ultimately too interesting, or much harder than they should be because of control issues. Outside of a very specific set of NPCs, the characters were pretty damn flat. This was a far outcry considering the wonderful characters of past games. Likewise, the plot was extremely cliche, you had to so mini-quests during the main plot just to continue it, ones that were extremely tedious, and last but not least, the cutscenes were extremely specific, which means you had to do the dungeons in one exact order, cutting out the fun of what Zelda games were about. Exploration and doing stuff when you wanted to do them. It was overall linear.
Link's Crossbow Training - To clarify, this is a spinoff of Twilight Princess. It simply was a First Person Shooter variation on the Genre, but also the first true Wii Zelda game, and not a port. The gameplay is very simple, and nothing ultimately any more unique than any other FPS, but it still was a lot of fun and came with an add-on to your control that allowed you treat your Wii Remote and Nunchuck like a Crossbow. There's nothing more to say on it other than it's the cheapest game to buy out there.
The Legend of Zelda: The Minish Cap - While it's a major improvement on the problems of Twilight Princess, it suffered from the same thing since A Link to the Past; a linear plot. Once again, you had to the dungeons completely out of order. However, this time, it was a lot of fun. All the areas were extremely fun to explore, even if you had to open up the game somewhat slowly. The problem with the plot is that you had to do mini-quests to unlock the next area. This is a problem that has yet to cease. On the other hand, this game introduced the Minish Cap, a remake of the Gnat Hat from the Four Swords series. It allowed you to shrink to a small size in particularly set up spots. While the game still has tons of freedom, and many cool items that were never used before, it still suffered from linearity in what you can do. It even closed off areas during the end of the game, potentionally screwing you out of the secondary appeal of the game; Fusing Kinstones for Secrets. However, the side quests are still more than high enough, and the gameplay was still fairly well done. Lastly, it introduced in-universe the titular Four Sword, a powerful item that allowed Link to become four forms of himself. The actual Manga gave each version different personalities as well. But let's move on again.
The Legend of Zelda - Phantom Hourglass: Remember what I said about freedom? This is where it started to lose it. One consistant thing about Link, outside of the first two games, is that he can swim. This has been erased. The problem is that there's tons of water, and you even have a Boat. Now, while this isn't terrible, and may not be too big of a deal for some, not everybody enjoys linearity and lacks of options. The next problem was the controls. You moved using the stylus, in a very fast-paced game. This was a poor design choice and only those with really good reflexes can beat the game. While it's true that it's not a hard game by any means, it was the fake difficulty from the Stylus controls that made it challenging. The silver lining is that you used them for items too, which was by far the best way to use them in a long time. The controls worked there. However, all the items were competeley recycled from previous games, meaning nothing new was majorly introduced. Even the enemies were just remakes of others. Although to say recycled items are bad isn't true, but every new game has introduced a new items so far. Likewise, this is the one and only games(outside of Four Swords) to not have Music used in anyway via an Instrument or relations.
The Legend of Zelda: Spirit Tracks - First, for the record, I have yet to play it. However, I have watched a full playthrough, and can atleast say some of the stuff fairly. The controls have not changed, however, you can control yourself much better than Phantom Hourglass. Likewise, the linearity is about the exact same. However, it got worse. Remember how I said that Phantom Hourglass somwhat restricted freedom? Now with this game, there is no Overworld to explore. You are completely on a Railroad, and are forced to follow a set ammount of paths that you unlock through the game. This is by far the major problem with it. However, new items were introduced, and it's still a lot of fun to go through and is much more challenging, albeit, sometimes too hard because of overly tough enemies, or struggles with the lackluster controls.
Now that that's over with, we noticed one thing that seemed to have happened. Freedom has gone downhill for the Zelda series for gameplay features, and by far the worst reason of all; Cutscenes. I love a Cutscenes every now and then, but when they're related to a forced plot that gives you one exact way to go, you know something's wrong. I can no longer explore the overworld? I can no longer swim? I have to use special controls when a D-Pad/Control Stick and a few face buttons could work better? C'mon, Nintendo, you forget what made them fun in the first place. Freedom, Good Controls, Puzzles, and unique Challenges. While not everybody will think it went "downhill", it's not hard to understand that the lack of an actual Overworld is going too far. I think I can be safe to say that atleast Spirit Tracks made a major mistake. Now, if I really wanted to be picky, I could go on about how graphics are more concentrated on than gameplay, or how the plots have dictated the gameplay. Okay, I mentioned the latter more than once. Here's hoping that Skyward Sword fixes this problem and keeps up the freedom of the old games, without reducing itself to a linear plot. While the plots were always somewhat linear, since you had to save the Princess(most of the time), you could do whatever the hell you want to get there. Let's bring back freedom, please.