Things KB has going for him:
1. The guy is a winner, period. I'd love to know the win percent of all his races. I bet it's a significant majority.
2. No one has been in the same class as him at 10k or XC (Strength).
3. World Record, WC, Olympic record holder.
Things KB has going against him:
1. Long term injury.
2. No races in two years (aside from a single poor xc showing in the snow).
3. The fact that he didn't try to race at all prior to WC.
The way I see it playing out is that his talent and training will get him in the lead pack at the bell, but he will get out kicked due to rust.
To play devil's advocate, some have hinted at the fact that maybe injury isn't quite the right term for his two year absence. If that's true, and his training is top notch, then perhaps he will blow everyone away after all.