Shump is a good defender that can be a stopper if he has good defenders around him. Unfortunately, not a lot of good defenders around him on Cleveland, but you could put him on a Derrick Rose in the playoffs and believe me he will do a better job than Kyrie would.
Smith is a cancer and will shoot 21% in the playoffs like he did when the Knicks were making the playoffs... distant memory
I don't know about Kyrie's impact on other players. He is a closer but he develops tunnel vision in clutch situations.