My favorite dark horse is Prokhorov. To me, looking at the player only in a vaccuum, he's a slam dunk to play in the NHL one day. Why? He's 6'5, skates very well, is mean and likes hitting and hurting people. If all else fails, you have an automatic massive 4th line energy player there. He's also a big body that you can just stick in front of the net and make him stand there. He absolutely loves it there, maybe as much as anyone i've ever seen.
Even if I consider there's a chance Prokhorov plays someday higher in the lineup, I fully acknowledge Kindel has skills that are much conducive to play Top-6. Stickhandling, smarts, passing, vision, edges, etc... But you need to be absolutely sure those skills are enough to make him fully translate to a Top-6 offensive game in the NHL. If not you have someone that will only help Hershey or Laval one day. If he even tries playing like Prohkorov he'll have the shortest of hockey shelf life.