I've brought this up specifically for Corpses behemoth
in the past. The fact that it's such an expensive Undead card means you're almost guaranteed to be waiting until the trigger to play it, particularly under the old Undead effect, and having it not happen can leave you at a severe disadvantage. This is made worse by the fact that you can't arbitrarily stack more Undead tokens to be safe since the scenario has it that playing any Undead WILL flip the counter. You're completely at the mercy of the random draw for an effect that is otherwise completely strategic.
I don't know if this proposed change is the best solution, but I do see it as something that needs to be addressed one way or another.