I'm not a Celtic fan, but I've watched Gonzaga for most of my life. I thought I'd share some of what I've gleaned from watching Olynyk the last couple years.
The first thing some may not know, although chances are by now you do, is that Olynyk has really only played as a big man 1 year in his life. Back before his redshirt year, Olynyk mostly hovered near the 3 point line and hit jump shots when open. He was not a true post player at all. This is understandable if you know about his history, particularly the fact that he was a very late bloomer and only became tall enough to be a post player his senior year of high school (and continued growing after that). In High School he was a point guard, so the transition he was forced to make after he suddenly sprouted 8+ inches was not an easy one to make.
The much publicized red shirt year was a direct result of Olynyk finally buying into the fact that he had to learn to be a true post player, and that the best way to do that was to step away from the game and train. The Olynyk GU fans saw from the '10 to '12 season was like night and day. The guy completely transformed himself. He bulked up extensively and suddenly was actually playing like a true post player. At times the guy was unstoppable, because he could combine a very good jumper with a surprisingly good amount of post moves. He improved a lot over the season as he became more comfortable with his new role, both offensively and defensively.
Why you should be excited:
*There's a lot of untapped potential. The fact he's as far progressed as he is after really only being a post player one year is quite remarkable. His offensive game can look like a thing of beauty at times, and I imagine that will only get better with time.
*Having been a PG previously he has above average ball handling skills for a guy his size. Combined with a great jumper, there's no doubt he will be good in the pick and roll if nothing else.
*The range on his shot is better than it looks if you are strictly looking at the numbers. Mark Few forced Olynyk to stay in the post 99% of the time, partially so he wouldn't go back to old habits. However, in the NBA there's no reason that he can't utilize that skill set more. His 3 point shot has potential to be pretty good.
Why you shouldn't be excited:
*While you can't discount his intensity, he'll never be a great post defender. That being said his blocks per game went from .7 his first 11 games last year, to 1.2 over his last 21 games. He is improving.
*Some of his post moves look like they'd be eaten up by an athletic big, considering they sometimes take a while to develop.
*One of the reasons he didn't always play big minutes was because of foul trouble. Part of that was because Few treated him with kiddy gloves and would yank him after getting two fouls in the first half and the other part is because he's apt to getting ticky tack soft fouls. I think the fact he's so new to being in the post is partially to blame, but it's something to watch for.