Meh. Barnes has the FT ability, but he just doesn't use it enough to really "give" him that skill. He did in the 3rd quarter last night, but where was it the rest of the game? The rest of the series even?
A wing to me is anyone who's not a big or a ball-handler/creator. So, like the Kings play 4 guards (Fox/Monk/Davion/Huerter) 2 wings (Keegan/Barnes) and 3 bigs (Lyles/Domas/Len) in their rotation. Huerter is a bit of a tweener imo where he can get run at the 3, but Brown has mostly refused to play him in that slot, so he should slide into the guard category. He has enough handle/passing/creation that I think he qualifies a bit more as a guard than wing.
So when you view the team in this scope, the glaring issue is the lack of defense with the wings and the bigs. There's not a single reliable above average defensive player in that grouping.