I don't know if he will end up being as much of a PF as Doan, but that's not to take anything away from him. I've never seen him play myself, but from all reports, he's a looking like a top 6 NHLer (obviously not of Crosby or Brule's caliber though).
I have seen Bernier play many times over the past two years, and one of his biggest flaws is that he gets lazy, sometimes seems like he tunes out of the game. I don't know if his head is always there. I have not read any sort of those comments pertaining to Latendresse. He's also got great size. Bernier isn't much bigger. They are both 6'2", and has maybe 10-15 pounds on him now, by the time Latendresse hit's the NHL, they'll probably be equal in weight at 220-225 pounds.
However, to be fair...Guillaume is two years younger, so we haven't seen as much of him, whereas we have a better gauge of Steve Bernier. Look at how well Bernier played his draft year, netting over 100 points as a 17 year old. The he falters the following season, not producing like we all expected. Or even take Adam Pineault for example, a kid who scouts were eagerly anticipating, then he goes to Boston College last year and has a poor season, netting only 4 goals. It doesn't look like Latendresse will hit any sort of road block, but I'm just trying to illustrate the point that Steve Bernier has had 2+ years of exposure.