i think that there is a bit of valid point to the whole bias toward rewarding roleplaying.
i also think that the other side has some valid points too.
on one hand, just saying something like, "i trick him" (roll dice); or, "i bluff my way past the guard" (roll dice) does lack something. if the player in question at least threw in a reference to something in the plot or an npc, or even references something like saying that he does what that one character in a movie or book did... that should be good enough to be going on with. i understand the desire for something more than, "i use my xyz skill" (roll dice).
on the other hand, sometimes my players are just at a loss. i try not to badger them for too many details, and in my own case, when i can't think of anything in character to say, i'll just be frank with the dm and say i can't think of anything, but here's the essence of what i'm trying to do. then the rest of the players or even the dm can offer ideas, or decide that my description is good enough, even if i wasn't able to roleplay it on the spot. roleplaying on the spot is not easy without lots of practice, and at least some familiarity with the subject at hand, even if second or third degree of seperation and non-experienced, to boot.
and yeah. if someone actually got up and entertained the group with an actual perform(dance) example, that should get bonus xp. heck, we give out bonus xp for great one-liners or cracking up everyone at the table with something. and that is totally meta-xp that sometimes has nothing to do with the in-game action.
my players consists of a ranger ( i kid you not, the man's an old-school survivalist), a (mostly anti-rp) tactician, a story-teller, an anime/manga freak, a devious quirky rp type, the understudy of the tactician and devious pair - except he likes rp, and a newbie. so i have to be flexible enough to handle everything from "here's my three pages of background, front and back - oh i was trying to hold back on the story line a bit, are you sure this little bit is enough"... to, "i suck at this, my character is great at this, so i use this skill here my sheets say my characters's good at and don't give me any crap about trying to rp something that i, the player, suck at", (rolls die), "oh look, a natural 20".... ^^
i think flexibility, with a keen awareness of what you've rewarded and to whom, is necessary to make it work out.