I agree, he can undoubtedly improve. He is the biggest and strongest guy on the roster, which provides him a niche against guys like Konate and Azubuike, too.
Developmental big men do tend to really start to come into their own around their junior year. I remember when we recruited Solomon that he was supposed to be a 6'6" power wing like Griffin, but turns out he came to Ames as a 6'8" post. I am sure he is still learning. Losing out on the past month of practice and game time from that really unfortunate injury has to be hurting his development, though, and he has missed time in the past, too.
He has always struck me as a high floor, low ceiling kind of guy, though. Dependable and steady, constant, but nothing really flashy or amazing. That is fine.
He is just stuck now behind (1.) a system that really only requires one post at a time, (2.) a consistent, but at a higher level, big man with an outside shot like Jacobson, and (3.) another big man who, when at his best, is one of the best to ever play the position at Iowa State. Solo is going to be a great backstop, but probably not much more this year.