Dude has terrific vision and really good hands. I think he has pretty good defensive instincts too. Good skater, though not explosive - at the NHL level his skating could be seen as a slight weakness at his size. And obviously his main weaknesses are size and goal scoring - he's small and has a mediocre shot that he doesn't use much.
I feel very unsure about how he'll turn out. He's got the potential to be a good middle 6 forward, but could also fail to make it in the NHL. In terms of Leafs prospects, I feel that Sandin, Robertson, and to a lesser extent Liljegren are all strong bets to be quality NHLers, while SDR is way more up in the air.