Fair enough, I focused more on your criticism of his performance rather than the overall show stealing point but in regards to that, I think it's valid arguement from a certain viewpoint. The card wasn't great and what made the Rock/Cena match have any value was the crowd reaction. This came from the polarizing figures involved, Cena being disliked by hardcore crowds coupled with Rock's history and incredible charisma, neither of their performances in the match created that reaction, it was already there they just had to show up.
Haitch/Taker was a superior match but it certainly wasn't a 'showstealer' in and of itself. The difference between that and the main event, in terms of drawing the crowd into the match was Micheal's performance, had he not been there it wouldn't have become the drama it was, so if that was the best match on the card then he was the best performer on the card.
I don't agree that he stole the show, for that to happen we'd have to completely disregard the main event and call it a one match card, that won't happen because of what it was and what it meant, but his performance as a character and what he added to his part of the card, made him the mvp of the night imo.