I do think the contestants will improve in terms of stage presence and pitch as they get a little more experience and confidence and a spot on the tour is no longer on the line. I'm also hoping that some of them will take a few more risks in terms of song choices once they make the tour.
Also, different song choices might force some of the contestants to improve their stage presence. If Stefano chooses a more uptempo song and isn't trying to look so sincere, he might open his eyes. Also, if they let Paul play his guitar, he might not move around like a drunk chicken on stage.