One of Wisner's moves that he excels at is hitting thin creases, and dodging solid hits, which makes him difficult to bring down when he's a solid target and there's no where to hide. When people talk about wiggle or being shifty, Tre has it. He's not fast, but can operate in a phone booth. I don't know that he's particularly explosive, but he is able to one cut and turn upfield. This is something Baxter lost, he doesn't have that extra gear or spring right before contact, or ability to cut and go. It's not just being able to run, it's fast twitch that just seems to be missing.
Tre is an excellent change of pace back, that gains as the game goes on and players wear down. This at times was also an indictment, because Sark would go away from plays there were working. Also, running takes time for backs to build a rhythm and settle into the game, which is difficult to do sporadically.