First of all, you act as if Thompson is some polished big man who has hit his stride and is clearly NBA ready, when he isn't necessarily a significant playing time player. Second of all, we don't need a bird in the hand right now. We stink, and we need to get better draft picks. How many of us were practically begging Theus to play the young guys more, so they can get experience? We all knew winning was irrelevant at that point.
The same holds true here. I'd rather take the guy who could give us two birds in the future, than the bird in the hand immediately. Thompson is a senior, playing against weaker talent, and thus we see what he will be like. You take a player who is a freshman, and imagine giving him 3 years to develop, and he's really good. Then guess what? He's the same age Thompson is when he entered. We don't need to win now. Sure we can take the few granted bricks that we get now from Thompson, but it's not as if our castle is going to be finished anytime soon, and therefore I want the guy who is going to deliver more bricks in the future.
I'm not saying I hate the pick, but I'm not saying I like it. However, this particular part of the discussion has nothing to do with that. It's the fact that him being a senior is indeed a knock on him, especially considering some around here consider him to be a sleeper.