The point is that making it removed on death neuters the effect. Bring two people with wipe avoidance and now they can simply swap off so that one of them loses the debuff every time.
That depends -- when it's used, is the debuff only applied to the people who rez, or is it also
applied to anyone alive at the time of the mass resurrection?
Consider a group with a mage and a rogue. Assume the rogue vanishes, the mage goes invisible, and the rest die. The rogue does the mass rez thing. Exactly
who gets the debuff?
If the debuff appears on everyone
including the mage and the rogue, and the ability to invoke
mass rez is greyed out when you have the debuff, then it's not completely neutered. No mass resurrection for a little while, unless you can get a regular resurrection in there somewhere (or a run from the spirit healer, or whatever).
Not being in the beta right now, I cannot run tests relating to this myself, but that's the only scenario I can imagine in which the debuff makes any sense.