Isn't Marcus Smart like 6'3 with a 6'9 wingspan? Pretty similar to Wallace.
If you want to compare Cason Wallace to Marcus Smart, I think that's a reach, not only because Smart has a 6'9" wingspan and an imposing 225-lb physique, but because he's more explosive and more powerful driving the ball on offense. He was a more capable scorer in college who could beat and bully his defender off the dribble and get on top of the rim. He was a consensus ~top-5 pick even as a freshman.
Wallace's offense so far isn't very advanced, so if you're really drafting him in the top 10 you're hoping that a) he's a game-changing defender at the NBA level, and b) his offense is going to flourish at the NBA level. Personally, I wouldn't take that deal in the top 10. I think Wallace should be a solid rotational player who can play 3D and knock down shots at an average or above-average rate. I think he has a floor that similar to a Deanthony Melton. Beyond that he has some drives and finishes that are encouraging. However, once you put him in an NBA context where nearly everyone on the floor is bigger than he is, he's not going to look like the same high-impact player that he was at UK.
Davion Mitchell looked like a stud at Baylor, but in the NBA he's turned into a 7th or 8th man for Sacramento. Size is a huge factor holding him back. Wallace is bigger than Mitchell, but likely only by a couple inches. Let's see how Wallace measures out at the Combine and then we can continue this debate. I've never known UK to undersell its players' measurements at their Pro Day. So when they say he's 6'3" in shoes with a 6'6" wingspan, I tend to believe them.
I don't mind Wallace overall, but I don't see him as a high lottery pick.