Well, we're only one game into the season so its awfully early to be thinking about this.
Couple things going against Pierce would:
a) be the fact that he plays with two other bonafide superstars and the Celtics are percieved as more a team than teams such as the Lakers or Cavs which, justifiably, or not tend to get looked at more as one man shows.
b) now that he's a champ, I think we can forget this media slight that has permeated for years about Pierce. He plays for a winner, plain and simple. However, I think day in and day out, sports reporting authorities such as ESPN & TNT play up the individual angle (Kobe v. Lebron etc....). The Celtics are the Big Three when advertised not Pierce v. Kobe. Like it or not, this is driven into the national conscious, media included. Come MVP voting time, more often than not, its going to go towards that guy who is imprinted in voters memories.
Don't get me wrong, I would absolutely love to see it. I'm just pointing out some possible reasons why it may be a struggle.