What we've seen right now about 4th edition is not much, people have so far also focused on the mechanical aspect of 4E saying its better, because well, it can be quantified. Roleplaying you can't really quantify in the same matter since that doesn't really change between editions, its only the options within said roleplay that changes (skills in 3.x for example, made alot of roleplaying with skills possible, multiclassing too made character development better fit.)
However there are also some very clunky rules (spellcasting the major one.) that I personally would like to see go.
I think 4E will be a good thing. One can always add optional rules in, however one cannot always take rules out of a game system which I'd like to do in 3.x
