I completely disagree with the majority opinion that seems to have Kelly Olynyk pegged as primarily a "stretch four." Yes, he has the ability to make some shots from deep, but I think that what gives the kid a high ceiling is the fact that he can do so much more than shoot the basketball. Right now, it doesn't even look like shooting the ball from the perimeter is the best part of his game. He can post up a little bit, he can face up and make small dribble moves to get a shot, he's a good passer, he can roll or pop off the pick, he's an opportunistic offensive rebounder, he runs the floor, and is a good finisher in transition. He also seems to have good hands, good awareness on defense, and a natural ability to read the game of basketball.
To me, Kelly's versatility is what gives him the potential to be a good player in the league. If he gets pigeon holed into the role of a stretch four, and used more or less exclusively as a guy who spots up from deep, then I don't think he'll end up being a very good player.
On the other hand, if he and Stevens and Rondo can figure out how to develop him into the well-rounded big that he looks like he has the skills to become, then I see a very bright future.