The lack of consistent aggressiveness offensively falls on Kelly himself. Overall, I have been very pleased with what we've seen out of Kelly this season. He's had enough moments where he has showcased his offense, and even taken over games for stretches of time, that we can say that the kid's got legitimate talent on that end of the floor.
However, he's only a sophomore, in his second year in the league. So, the fact that he doesn't feel comfortable being the go-to guy for the duration of the game isn't all that surprising. He's a team player, and I don't think he wants to step on toes. It's almost as if he says to himself, "wow, I'm playing like a star right now. I better tone it back before it falls apart. I'll take what I've got right now."
Obviously, this is not the mentality we want out of a player as offensively talented as Olynyk, but I think with time, as his confidence continues to grow, he will increasingly start to feel more comfortable in his role as a primary offensive threat on this team.
I'm happy with his development thus far, and look forward to watching it continue.
As far as his defense goes, I really think he's been put in an impossible situation for him to succeed. He needs to be paired with a good interior defender, and not be counted on to be the team's last line of defense. Nobody ever expected Kelly Olynyk to be a defensive presence in the paint as an NBA player. It's simply not what he is. This doesn't mean he can't be a very good power forward (or--dare I say it--small forward) in the league.