As it happens, I'm not that broadly versed in RPGs. Probably 80% of the RPG games I've played since I started seriously gaming in 2001 are Final Fantasy games, and most of the rest are BioWare. So it's not like I have a large basis for comparison. (Aside from these two series/publishers, I play mostly puzzle, platform, and casual games.) And the FF games and BioWare games are quite different from each other, which makes it difficult to compare them. But a couple of thoughts.
Probably the evolution in RPGs I am enjoying the most is the move toward voiced protagonists. I generally connect more with the Final Fantasies that include full voice acting, and in Dragon Age 2, I found that Hawke having a voice added many more dimensions to the character. It makes their interactions with party members and NPCs feel more natural. And I'm sure I wouldn't have enjoyed the Mass Effect series nearly as much without the fantastic voice acting of Jennifer Hale as Commander Shepard. I'm sure it's a matter of taste -- I know some people prefer a near-tabula rasa protagonist, like the Warden -- but I find I prefer my player character to be a character, or at least the outline of one.
If that doesn't count as gameplay ;) then I vote for the emergence of casual mode. Sometimes, I just don't want to be stuck on the same boss battle for five million years. I want to hack and slash and move on with the story. So the ability to turn the game down to Casual, then bump it back up to Normal when I'm ready, is a lifesaver.
As for evolutions I don't like? That's harder to pick. Sometimes I miss the turn-based battles of Final Fantasy X -- the ability to move through battles at my own pace was so important to me as a gaming newbie. But everyone is moving away from that, including the FF series. This isn't a 100% dislike, though, because I also really enjoy some aspects of more modern system (I loooooved Gambits in FFXII). So I guess I can't really pick on any general trends I don't care for -- it really depends on the game, and on how things are specifically implemented.
This entry is also posted at http://owlmoose.dreamwidth.org/660125.html. There are currently comments on DW.