He has bad footwork. The feet aren't the problem, though. It's the large amount of side tilt and hip motion that makes the feet look sloppy. The ankle injury didn't help but mechanics were off before that.
His mechanics at FSU were not very good. Hard to change when you're playing baseball, and baseball is the main culprit in those mechanics. That said, it's a long-term advantage because Winston was forced to have tremendous anticipation.
Right now he's stuck between two patterns: the revised George Whitfield motion and his old tactics. When blitzes come (which Tampa obviously can't contain), the old motions come back by default. It will take at least another off-season before you see a meaningful change.