Any specific examples? I know for that some of the newer classes take advantage more of the additional controls (Q, hotkeys 1-4, space bar); I did show you that expansion design document a while back, and some of the older classes may be getting some newer things for these controls. However, with more careful and current testing, some classes are definitely fine and not in need of more options. For example, I really doubt that Anna, Slain, Iji, Sorceress or Xan need any more buffs, because they're all complete classes.
In any case, I think it just has more to do with people playing the newer classes more often. I bet I can roll with any of the older classes and beat down any of the newer classes. Hold dat.
Edit: I've fixed diagonal reflection physics so it is much more accurate now. This applies to Meower ball, Xan shrapnel, and Rosie Grenade bounces. It feels really good to bounce nades off of walls/slopes now.