I think you mean Okoro. Okafor was a clear bust. But we have different definitions of busts. Sexton can probably be a sixth man of the year in the NBA, and if you're picking at No. 8, you could do far worse. If he goes to a team that has the right kind of personnel, he can be a poor man's Kyrie next to a poor man's LBJ. The Heat had Herro on the table for him this summer and the Knicks had at least one pick and Toppin on the table. Teams don't offer anything for busts. There are plenty of players selected in the top 10 who don't even have the final option on their rookie deals picked up because they're not worth the cap hold. See, e.g., Sekou.
I have concerns about Okoro. He appears shorter than advertised and that's making him look more like a SG than SF. But, if you look at his shooting splits from last year, he was a far better shooter at home so there's at least some evidence his jumper isn't flat broken. The other thing is that when you're drafting 19-year old players, particularly works in progress, you need to give them at least two full NBA seasons. Garland looked awful his rookie year. Bey appeared to be the best 3&D prospect from last year's draft but he played two years in college, was older, and viewed as being pretty close to his ceiling. It's why he was still on the board at No. 19. You really shouldn't be drafting guys like that in the top 10, let alone top 5.