Especially if you play it correctly. Every team runs a choiced pokemon (or should), switch into the choiced pokemon and you have your kill. Wob can also come back repeatedly with Wish support. Wob can also run encore if he runs into a pokemon that is able to set up to kill him, letting you effectively bring in the counter. Blissey and pokemon that can use trick are not counter because you dont switch into them. You have someone else kill them (blissey) and only switch in after the kill.
Wob is the ultimate Revenge Killer :/
Wob is the ultimate Revenge Killer :/