I never said she needed to be killed, just not able to be Warchief anymore. As I stated just before, they could have keept Vol'jin as Warchief, and just put Sylvanas into the spotlight. They never needed to make her the Warchief in the first place. I don't mind or care that she get more attention, whatever they make her as a Villain or a Hero, but I personally don't want her as a Warchief.
Also I have to correct myself, she does do one thing, the thing she does in Stormheim ain't really any good of what I can tell of, but perhaps I am wrong, as we never really saw what her fully intentions was with it. Perhaps it was something for the better for the whole Horde, but I have serious doubts about it untile proven otherwise.