Dillard was a tire fire for TEN last year; 12 sacks in about 560 snaps. They benched him. Rumor is Myles Garrett schooled him so bad that Garrett was giving him blocking tips after the game.
I would consider a training camp body/depth move with the whole "competition" thing in mind. Maybe Dillard can get you thru a game, but I don't think you ever want him as your starter.
He won't impact draft strategy at all, aside from giving them more freedom to pick a developmental OT vs. one they might need in Game 3 should Walker or Tom twist an ankle.
And yes, Dillard's a good athlete, but there's enough pro tape to tell you that he's not a starter. This is like signing Byron Bell. Dillard played in an Air Raid offense, and those players tend to struggle to make it in the NFL. If anyone can get something out of him, it's GB. I wouldn't hold my breath -- PHI sure tried, and they've fielded some pretty good OLs.