>>3771570 (OP)KH1 is kinda rough around the edges and all of its superbosses (aside from maybe Kurt Zisa) kinda suck, but you can really tell they put their all into making it and it's really charming in spite of its flaws.
Later games kinda feel like they're trying to ape a lot of what KH1 did, but while going through the motions. The Ansem Reports in KH1, for example, are collectibles, but it's also implied that Sora is actually gathering them and reading them (aside from maybe the three Final Mix ones) in order to refute Ansem's world view at the end of the game. In all of the other games, the reports are just random lore notes tucked away that are never discussed. Ven just suddenly gets a letter from Xehanort to Eraqus after leaving the Land of Departure that outright shows Xehanort was setting Terra up to fail, but this has no bearing on Ven's experiences nor does it affect the way he sees Xehanort.