I've always thought Clayborn was a better 3-4 DE prospect than a 4-3. I think he could play both well at the next level, but I think he could reach his max potential in the 3-4.
I don't think he's the "Pure" Pass Rusher that is needed in a 4-3, as he is not an elite athlete with elite edge speed. In a 3-4, you want more a of a bull at DE, and I think that suits AC more. He has a very high football IQ, which is always a plus, regardless of system.
He is big enough to handle the DE position in the 3-4. While he may not have top end speed, I think one of his biggest attributes is his first step quickness. He gets off the ball very quick. I think one thing that makes him a great fit for the 3-4 is he is very quick off the line, but then he can just lay the hammer on you and bull you over. I've seen more than a few LT's over the past 3 seasons rush to cut him off outside only to get dropped by a bull rush move.
I think he does a great job using his hands and getting off blockers on a consistent basis, which will help him fighting double teams and chips that will come at the position. I've seen some people question his motor, and I don't buy it for one second. I've seen every snap of his career and never have thought he didn't give it his all. He may have had endurance problems this year, but those were made even more apparent because he never relents
I think he'll end up similar to Darnell Dockett if someone drafts him for the 3-4. More than just a run stopper and someone to take up blocks. I wouldn't consider him prototypical 3-4 end, but I wouldn't consider him prototypical 4-3 either. He'll produce against the run and the pass though, wherever he ends up though, I'm certain of that.
As far as Ballard goes, I love his potential. The unfortunate thing is I've loved it for the last 4 years too. He is pretty damn athletic for his size. I wouldn't say he didn't produce, or his production was low, but with his size and athleticism, and playing beside an All-American and 2 other NFL DL prospects, he should have been dominant, and he wasn't, even though he flashed he could be. The plus side is he's only played DL for 4 years, so there is still room for growth, and if he can put it together, he could be nasty