I wouldn't say that Link's Wolf form, as in parts of the game where you are FORCED to use it, as opposed to optionally using it, even make up 30% of the entire game, let alone half. I can appreciate the OP just not caring for those parts of the game, however, I thought it was a nice and unique touch, especially for the usefulness of following scent trails and finding spots to dig up hearts and roopies, etc. To each his own, but I personally adored Twilight Princess, it's still my fav. 3D Zelda.
As for games that have outright disappointed me the most, there have certainly been many, but I'll list a few major ones.
Star Fox Assault - I hate this game because I allowed myself to be duped by it pre-release. I saw the early trailers that mostly only showed the first two levels of the game, which happen to be basically the ONLY good levels in the game, and I was blown away. For it's time, it looked amazing, graphics, gameplay, music, you name it. I had a swell of hope that I was in fact getting the proper sequel to SF64 that I had been long awaiting. In short, I was fucking stoked beyond belief. I had even read about, and didn't exactly care for, the notion that there were going to be parts where you got out of your arwing/vehicle and walked around on foot. I never liked the sound of that, but I naively figured it would only be a small part of the game, because I mean OBVIOUSLY, why would they fuck up the perfect SF formula, right? Well, they did. I managed to avoid most spoilers, including early reviews I guess, because when I bought it, I played those first two levels. Loved 'em, though I was in for one hell of a game. And then proceeded to learn the hard way that literally around 85% of the actual game, at least, is "Get out and walk around" missions, that by the way play like absolute dogshit. To put it mildly, I was heartbroken and depressed. I have never gotten THAT excited for a game, and then been THAT let down. Ever.
Pikmin 3 - I truly hate to have to include this game, because unlike SFA, it is NOT a bad game at all. However, as someone who absolutely loved the first two Pikmin games, I had been waiting for years and years to finally get a third game. I was so excited when Miyamoto let slip that they were in fact making a new one, and I eagerly awaited it as a Wii game. Then I was at least somewhat disappointed when it turned out it would be a Wii U title instead, but I was still excited, and even somewhat positive about the fact that the graphics would be even better, etc. Unfortunately for me, there were no early indications, either that or I simply missed them, that the things I would wind up disliking about the game even existed. The main issues I discovered, quite quickly, that I don't like about an otherwise fine game, are things that for some facepalm worthy reason, Nintendo decided to simply remove from the equation, as if the development team hadn't even bothered playing the first two for reference. The most maddening, is the exclusion of the "c-stick" swarming functionality. Pikmin, contrary to what some might seem to think, is NOT a game simply about picking up and tossing Pikmin creatures at various enemies and obstacles. Swarming, and the ability to MANUALLY make them swarm and MANUALLY move them around you so as to avoid hazzards, etc., was increadibly useful and only added to the deep and strategy-laden nature of the series. Removing that feature, I feel, was the equivelent of removing the ability to run in a Mario game......you can play it, and it might still be enjoyable, but the gameplay just feels neutered somehow.
The other main issues, while lesser in nature, are still sticking points that I really don't like. One being, they also inexplicably took out the ability to ZOOM the fucking camera in or out. Nope, you're stuck with a static-ass camera angle that you cannot change, even though there are COUNTLESS times in the course of the game that you really could use some zooming action. The level of camera control Pikmin 1 and 2 afforded you, at times, was almost as integral to the strategy and gameplay of it all, as the c-stick swarming function. Sure, they replaced what easily could have been using the right analog stick as the c-stick swarming, with the ability to manually ROTATE the camera around, which granted can be useful. But you could already quickly change your camera focus (ala 3D Zelda) by centering in the old ones. And the ability to rotate the camera, still does not replace the far more valuable ability to zoom in or out, or even get that z-trigger "overhead" view. All of that made the first two games, in my humble opinion, FAR more playable, and enjoyable TO play.
The third issue is the least, but it still sucks: For some insanely retarded reason, they felt it was okay to only give the player ONE available save file slot. Meaning, that if you start a new game, you have to automatically DELETE your previous game. I found this out the hard way, as I started a new game to show my friend the opening. Man, was I sure happy to discover that little nugget. It just makes SO little sense to ever do that to a gamer, 3 save files (if not more) has been standard since fucking Zelda 1 on the NES, and it has CERTAINLY been standard in most Nintendo games since then as well, even on modern console. The first two Pikmin games gave you three save slots. But nope, the great and mighty Pikmin 3, in all it's pretty HD glory, only lets you have one at a time, meaning you better get used to erasing old games, or NEVER starting a new one, either way.
Now I've said far more about this game than I have Star Fox Assault, but that is because I actually have to point out the things I don't like about a game that I otherwise do think is still "okay". With SFA, it's just a steaming pile of shit outside of the first two levels, and that is about all that really needs to be said about the game. With Pikmin 3, it's much deeper, because at it's core, it has the makings of what COULD have been a fantastic game. In fact some people seem to really love it, and while I believe that most who have this opinion have never played the first two, some even claim it's the "best in the series". I'm afraid I must report that that is hardly true at all. Those missing aspects really hurt what could have been a very good game, even though I do prefer treasure hunting "finding fruit to save your homeworld"...I could get over the lack of treasure. Or the lack of Captain Olimar, or the mysterious abscenes of the Purple and White Pikmin in the main game. The game is decent, and had it HAD manual swarming and camera zooming and multple save files, all things it SHOULD have had in the first place, I really would probably love it. As it is, I do like it....but I cannot help feeling incredibly disappointed and let down.
Metroid: Other M - To me at least, basically the same deal as Assault, with one major caveat: I had a sneaking suspicioun that Other M was going to suck dogshit from the moment it was revealed that Team Ninja was developing it. In this man's personaly experience, Team Ninja has NEVER been a good developer, and their games, especially the Ninja Gaiden titles, have always had a slew of issues that make them feel half-baked and just not all that fun to play. I was afraid that this would happen to their "Metroid" game, even though I also hoped that Nintendo would make them "do better". Nope, as it turned out, my initial feelings were right. The game sucks. I know it has it's fans, but the easiest way to sum up, to me, why it sucks, is simply to say "It doesn't feel like a Metroid game". That is the quickest, but also most condemning way to describe it, because honestly, it's true. It simply doesn't feel like Metroid. Even the Prime games, as impossible as first person Metroid once would have sounded, somehow manage to feel like Metroid. Other M does not. The story sucks, the gameplay sucks, the whole damn thing sucks, and while I saw this one coming, it was still a let down, that Nintendo would allow one of their greatest franchises to be treated that way.
Tekken 6 - There simply seems to be something about even numbered Tekken sequels, with the exception of 2, and them just not being any good. Tekken 4, most fans rightfully regard as a "misstep in the franchise", and that's being polite. Tekken 5, however, was (cheap as fuck last boss notwithstanding) pretty amazing, especially all the content they crammed onto a PS2 disc. I was, naively, fully expecting them to give 6 this kind of treatment too, and thus it was the only PS3 game I have ever pre-ordered. Well, long story short, it came out, it was very underwhelming, the regular single player "play to unlock characters and endings" mode really just played like dogshit, and the only positive thing the game really seemed to have going at all, was online play. I was just very let down by a fighter I was unreasonably excited for, and thus Tekken 6 became one of the only games I've ever taken back in less than a week's time. I traded it in for store credit, which I immediately used to pre-order New Super Mario Bros. Wii....and honestly that was a great investment.
There are many others, such as Mario Kart: Double Dash, Castlevania: Lament of Innocence, Super Mario Sunshine, Zelda: Wind Waker, etc. etc. but that's all for now.