Here's the issue with a lot of college big men. In college you can play inside the paint, post up and dominate with a 6-9 frame. In the pros you can't (generally speaking).
So when Tristan announced he was forgoing his final three years of eligibility, I scratched my head. I thought a guy like Tristan, most any 6-9 college center, should learn the power forward position before trying it at the next level. The problem that a lot of these guys face is that once they do get onto an NBA team, there are only so many minutes in a game, and if they aren't refined, sometimes finding floor time can be a struggle.
With Tristan, I would have recommended at least another year in college. What I would have done, had I been him, would have been to develop that true power forward game. He's got the body and he's got the talent, but I think at 6-9 in high school and college, you are a center and don't have the requisite skill set at the next level.
Conversely, if you look at who stayed in college, this might have been the perfect storm for Tristan. With, and Perry Jones all returning, big men were a t a premium and I think Tristan just struck while the iron was hot.
I do think he will one day be a guy fans can rely on, but he might have a year or two growing to do before he gets there.
But I guess if you can go fourth overall, go.