Something that was discussed relatively often around the release of third edition was the phenomenon of "third edition blandness" - and after switching from second to third in my campaign setting, I noticed it too. In second edition, there was a strong emphasis on class identities. That is, paladins should act like paladins, rangers should act like rangers, and part of the DM's job was to play watchdog to make sure this was followed.
If you peruse the third edition literature, especially the additional class books, the idea seemed to be more to supply the hit tables, feats, etc. instead of the ambience of the class itself. The difference is less defined in the PHB, but it's still there.
But this isn't all bad.
Because of the concepts of the classes were more defined in second edition, it didn't give quite as much personal freedom to the players. In third edition, it's significantly easier to make that gladiator class fit your character's history, instead of trying to work around the narrow scope of the class.