What's with the hate on KH2?
It had a better plot.
You had more control over Sora.
SOME things were hard.
Camera was better.
More variety.
Everything was FLASHY. (I personally don't care too much about difficulty if what I'm doing looks like total rape.)
I do not agree that Kingdom Hearts 2 had the better plot, but I do believe it had one of the best groups of antagonists in video game history (they actually had a MOTIVE, though their leader was just using them all; I'm not going to argue for the Organization right now, however).
Many people dislike Kingdom Hearts 2 because of its linear, repetitive and casual game play. Many also dislike Organization XIII and the new characters introduced to the series.
My personal qualms with Kingdom Hearts 2 were that the battle system was screwed around with (the first Kingdom Hearts had a great battle system IMHO and was difficult in many respects) and it was short as balls. I don't really mind a lack of difficulty when it comes to RPGs (specifically Kingdom Hearts) because I play them for the story, but many do.
There will always be a lot of people who hate the game. Kingdom Hearts is my personal favorite game series and Kingdom Hearts 2 is an integral link in that series, while admittedly not the strongest link. I preferred 358/2 Days (which I think even more people hated than KH2) but that's me.
P.S. I would most definitely prefer Chain of Memories as well iif it weren't for the battle system - that ruined the game for me, both on the GBA and on the PS2. If I wanted to fuck around with cards, I'd be playing Yu-Gi-Oh.