It seems that the mentors they've brought on this year are geared towards promoting stage presence, and Adam can certainly tell them a thing or two about that. Although, the singer-songwriter, instrument-playing types aren't really geared toward "owning the stage" in a physical sense. Actually, I'd really rather not see most of them trying to go for it on stage the way Adam has.
His vocals could be both very good and very grating, but Adam could always put together a memorable performance. And I think he'll be very positive with all of the contestants. Lord knows, some of them need some encouragement after some of the comments they've gotten from the judges.