That describes a generalist as opposed to an actual top ranked performer for any given character. Sure they can use a wider field of characters, but as generalists I would not expect them to be able to land the same shots as a one trick or similar. The latter requires a lot more dedication and practice, so the muscle memory will not be the same. They will be at a disadvantage when trying to mirror against such an opponent.
Hero bans were tested before, and it ended quite badly. I do not know why it is coming back, but I do not expect much support from the top tier specialist players since they cannot operate at their absolute best.