If you turn your head and squint, Walker kind of looks like Haasan Reddick. But there's way too much projection to his game to take him top 12. The hype around him seems insane to me. The only way I can explain it is his one huge game against Texas.
He hardly played at Georgia, he wasn't very effective as a pass rusher when he did. A lot has been made of the Georgia DLs never putting up counting stats, but they usually have pretty good sabermetrics and rate stats. Walker doesn't have those, he just did not win very often. He's not much of an LB either - I think his clear NFL home is as a pass rusher. But he's sort of a raw ball of clay there.
He's a really good athlete, and he's all football player, and you know he's willing to put in the work. So I could see how he could put it all together and be an impact player. But you're picking a not-great pass rusher and hoping that he turns it around in the NFL. That's a crazy bet to take in the top 10 when you have dudes likes James Pearce still on the board, who's already been beating the same tackles that Walker hasn't for two seasons.