Two things I liked about him in college was his lateral movement, and very good reflex action. Along with his size, footspeed and ballhandling skills that a lot of big men don't have, he was an enticing package. His post skills however were raw, and he was strictly right handed. He had then, and still now, an inclination to always go to his right. But when you consider that he shot up from 6'3" or so to 6'11" in just under two years, one can understand his underdeveloped post skills.
As I've said before. If he can develop a good post game, and it is an IF, he could become a star in this league. Hell, you can become a star in this league just being what Bricky calls a garbage man around the basket, if, you can play defense. While he may never become a great shotblocker, there's no reason he can't at least average 1 to 1.5 blks a game once he develops the right technique and footwork.
This may be a small thing, but I've already noticed in the limited time we've had to see them, that Thompson now has his arms straight up in the air when defending a player in the post. Last year his arms were up, but angled out over the offensive player. An instictive thing to do when trying to block a shot. But you'll get called for a foul every time when the player goes up for his shot. Just that one small change will decrease the number of fouls called on him, and to a smaller degree, increase the number of offensive fouls he'll draw.