I played the games a bit out of order, and so I didn't play KH2 until after Days. Yes that sounds crazy, but when Days came out I had no idea about the Organization or the Nobodies or anything. I treated it as simply a continuation from CoM. Roxas was like another new character for me and seeing him grow over the course of the game was great.
In fact, KH1, CoM, and Days are my favorite games in the series. I actually preferred when the games played clunkier, featured more regular platforming, and weren't just spam fests. Puzzles and dungeons galore.
When I finally did play KH2, at first I was super excited. After Days I was looking forward to seeing the next big step, maybe Roxas and Sora fighting the Organization alongside one another, maybe the Organization (aside from Xemnas) developing into deeper characters than just "we're the badguys".
But then the game just ditched Roxas, brought Sora back but made him an anime shonen protagonist who lost a lot of the maturity he had built up before. The game was far too easy, the Organization weren't even doing anything for most of the game, and the world design was bland and simply just corridors.
It is for those reasons that I have the most unpopular opinion, that all of the current problems the series suffers from had formed in KH2, and that "smooth gameplay" isn't enough for me to like it at all. As slow and repetitive as Days was, from my perspective it fit well with KH1/CoM. KH2 is bottom barrel for me. And personally I treat games like a story, a book or world that I escape in, not as a test-of-skill button presser. KH2's value is only in that department and so it is my least favorite game.
In short, I'd rather the games be slower and clunkier to move around in if it meant the story and characters were deep.
Spoiler
