The only thing that RUINED TP for me was the map was too freaking huge. I got lost soooooooooooooo many times to the point where it was a puzzle just to get where i needed to be and in my opinion if its that bad its flawed design, not lack of players ability.
Twilight Princess wasn't as good as the other games because it didn't seem to carry the same magic as the other games did. It wasn't very hard, the rupee system was broken, the overall atmosphere was too realistic, and the music wasn't as catchy. It is still a phenomenal game, just not as phenomenal as say, Wind Waker or Link's Awakening.
Overall TP is great, but the main issue with it for me is that it tries too hard to be "dark".
It didn't NEED to be dark, the overall storyline was pretty basic and I felt that it was just being dark for the sake of being dark. Midna's character I think sorta saved this game for many people though.
I really don't understand all the hate that this game gets. I think that it's better then OOT.
Twilight Princess improves upon everything that OOT did.
I also like that it's not a simple good vs evil game. The game has alot of grey areas that make you think. You have to wonder if the gods did the right thing sealing Midna's ancestors away for all time. Do Midna and her people deserve to be sealed away forever because of what their ancestors did?
Hyrule felt more real in TP then it does in any other Zelda game.
Plus the characters have more personality as well especially when compaired to Ocarina of Time.
All in all Twilight Princess is a great game that gets unfairly bashed.
It's easy for anything to be disappointing if you set your expectations too high. I had this problem with almost every Zelda game since Majora's Mask (which I thought wouldn't be great for some reason and ended up being blown away). It's the people who are disappointed who have a problem so I wouldn't worry much about it if I were you.
I have a lot of experience at being disappointed by video games because I constantly expect more than I receive. If you're an optimist just don't let pessimists like me bother you. Just ignore us, and enjoy the game. And just because lots of people were disappointed by Twilight Princess doesn't mean they didn't enjoy it. For instance one of the few Wii games that didn't disappoint me was Donkey Kong Country Returns, but I still would say I like Twilight Princess more even though Twilight Princess disappointed me tremendously. It's like for DKCR I expected an 8 and got a 9.4 and for TP I expected a 10 and got a 9.5. Disappointments can still be really good.