First off, who cares what Roves says. Secondly, if Trump mass fires Obama holdovers and congress obstructs replacing them it may well cause more problems than going slow. Remember, Trump not only has to deal with the Schemer led Dems but with opponents from within his own party.
Trump is an amazing man in an incredible position. He is uncommonly astute, in my estimation, and I have to put my faith in that.