Based on draft write ups and some highlights I've seen, I'd say it seems he has GREAT explosive quickness, but might be a one trick pony where if you can handle that quickness you might be able to handle him.
Didn't see a great deal in the way of power or toughness...
So I'm seeing a pass rush specialist, which will be need to be protected to stay out of the more physical roles/calls. If he can drop back in coverage, that all around great quickness could be a huge asset, but that's a huge if especially if another smart team like the Ravens couldn't make it work.
I see him as a pass rush, ST block the kick role, and could potentially grow but right now he's limited... but he could become Fackrell replacement as he's a FA.and we just spent a lot of money/draft investment at OLB.
Though Fackrell is a lot more versatile (coverage long arms which help keeps guy off of him of him on the edge), Williams is quicker and when he was able to beat the blocker often seemed to be able to track down the ball carrier quickly.