What it always comes down to is work ethic. My favorite thing about Chris Mullin isn't his shooting ability, his star power or his overall professional success. It's the stories we hear about the time spent in the gym working on his game.
Willie Shaw was more talented than Lavor Postell. As a freshman, Shaw looked like a future NBA player. The star that Wesley Matthews eventually became, should have been Willie Shaw first, but he was lazy, and immature.
If Yakwe has Lavor Postell's work ethic, and from his play, I think we can determine that he's similar in hustle, there is no reason to think that improvement of a similar degree isn't likely. I think the real question marks, Sima, Mussini and Ellison have further to go because physically, they were overmatched against high major opponents. That doesn't mean they won't get there, but the fact that Mussini and Sima are staying on campus this summer to get stronger is a great sign that they have recognized a key area that needs improvement. Good for them.