I think this series rocks. My last playthrough of the original I put 80 hours on. I got EVERYTHING. It was magical. I tried to pick up the second again a few months back, but I dunno, something about it was just not quite the same. After several years, I think it's safe to say that in KH2, Sora was not as approachable as he was in the first game. He seems to have more of his crap together, so his is not the best perspective to unfold the story from. Also, with Sora able to massacre more effectively, he didn't seem as helpless, leaving the audience unable to identify with him, to some degree. I guess it's also worth mentioning that nearish the time I started that replay I took a Skyrim to theā¦.well, you know what I mean.
All of that aside, KH2 was fan-freaking-tastic. The story, though confusing, is great. I think when you're dealing with Kingdom Hearts continuity, you can't look in to it too much before it stops making sense; take, in the first game, where Riku pulls a shadow/heartless out of Sora on Hook's ship. Later in the game, spoilers if you haven't finished the first game when Sora becomes a heartless, he's a measly shadow (the heartless kind, not the cast on the ground kind.).
On another note, 358/2 days was a big letdown for me. It's one of very few games I've played whose story had nothing (or very little) to do with the gameplay. Really, the only reason I finished it was because the story WAS interesting. But oddly enough, I didn't actually enjoy playing the game.
Final thought: Atlantica, in any game, is a TV-mutingly, infuriating, hideous pile of rotten garbage. I HATE Atlantica.