Nobody thought Thon Maker would go lottery, nobody thought he could play at this level at this stage. Look at Thon's per 36's and the impact he's had defensively starting in the playoffs for Milwaukee. Going forward he's going to be their starter as early as next season. Everybody thought we reached on KP and they said he was too skinny to be a contributor in year one, dude was damn near RoY.
While I agree with you on College being overrated, I wouldn't draw any comparisons between Thon/KP and Hammy, mainly because of size. They're legitimate 7+ footers and even if their offense doesn't come around they can still alter shots and be a problem on defense.
Diallo has a lot of potential, but taking him at 7 is a huge reach, if he were 6'8 with the same skillset and athleticism it would be different, but at his size it's a real gamble.