Alright, I'll put this out there as my pick for the prospect who is poised to move up the most in the next year or two....
The prospect everyone is sleeping on is not Johansson, or Veleno. These guys are top-5 on almost everyone's lists. It's Robert Mastrosimone. I think everyone probably has him ranked too low, including myself, and especially those who have him outside their top-10. A prospect not often discussed, Mastrosimone is a fan favorite for those who watch him. His skating isn't bad, but it isn't great either. It's something he'll have to continue to work on, but he's one of those players who's lack of elite skating ability is mitigated, and often not even noticed, given his elite work ethic, compete, and confidence. Not very exciting qualities? Fine, but they are supplemented by a high hockey IQ, high skill, and an excellent shot.
This kid drives the pace and makes players around him better. To borrow a military term, he's a force multiplier. He consistently wins board battles against bigger guys, never hesitates to block shots, and never stops, always going through walls. Selfless and coachable. He also always seems to raise his game in playoffs, tournaments, and otherwise big games. He has what many message board hockey fans hate to hear: all the intangibles... but with enough skill added to the mix to be a middle-6 winger. He has the makeup to be very versatile, able to move up and down the lineup. Edit: And after writing all that, I feel like I could also have been pretty nearly describing Tyler Bertuzzi.
I expect Mastrosimone to move himself up a tier in the next year or two, into that grouping with Berggren, Veleno, and Johansson. If you have him ranked outside your top-10, you're sleeping on him.