I don't mean to single you out but you are the topic starter and I just didn't feel like quoting the other 25 people with similar posts.
Now what I fail to understand is why you all think people who don't like KH2 automatically hate the game? A lot of people just don't like a lackluster story that was overshadowed by the hand held game that came before it or a game that has such easy game play that another game had to made to make it harder. You don't have to compare KH2 to KH1 but since it is the sequel to the first one it is going to be compared since it is an extension of the first one, it's not a spin off so it shouldn't be singled out as one.
Yes KH2 had some good improvements like the camera and better graphics as well as drive forms but those things to most could not hold the game up to such high regards. Game play like I said before was far easier than anyone expected and the story was mediocre since half of the story has nothing to do with Org.XIII and the other half felt like it had no real balance with the Disney characters/worlds and the story. Then there is the unnecessary characters like Tifa,Vivi, Setzer, Yuffie, Cloud and Sephiroth who where either there to aid you in one fight or there for no real reason at all but to make certain fans angry.
You say that game play and story are only two aspects of the game yet they are the most important. Why would you play a game if you don't enjoy the story? Why play a game that isn't even a challenge for you and makes you bored every time you play it? Oh yeah the graphics and voice acting are good so that must make it worth playing, well for most that does not make a game worth playing it makes some sort of pretty CGI movie and most didn't buy a movie they bought a game. You can't just throw out the other important things just to make it look and sound pretty especially when the last two games were considered great in all aspects.
That's my opinion of why I don't think KH2 is a great game.