Most of the games' weaker spots were remedied with outstanding positives (for instance, the lack of post-game in BW was made up for with a phenomenal story and characters), so I end up not being so disappointed by them.
Really, I think the only thing that disappointed me, that I feel would have actually benefited the game if they had done it, is if the Striaton Gym battle had been a Triple Battle. Looking back, it's kind of a minor thing, and I really only remembered it because I saw a picture of the three Gym Leaders recently, but I think it would have really helped implement the new battle style more, and further add to the uniqueness of the Gym. If they wanted to keep it in line with the "Black:Rotation::White:Triple" thing they had going on, they could have been a Rotation Battle in Black and that would have been appropriate, too. I guess it seems more like a missed opportunity than a disappointment all these years later, but I can remember feeling disappointed about it at the time, especially when Triple and Rotation Battles weren't really implemented into BW all that much.
It would have been nice if they expanded upon the lore presented within the Abyssal Ruins, too. It draws clear parallels to the ancient king and N, but it would have been cool if there was more to do there to further hint at the ways of the ancient civilization.
