This would enable people to apoc zombie something forever, and block other people from content. Any system that is added that does not allow stuff to go unclaimed until everyone is dead is a very bad idea simply because it would enable people to block others from being able to do it. Now, if they wanted to add a 10 minute depop timer to every NM inside abyssea, I wouldn't care if they added the claim system you advocate, because that would defeat the ability to hold mobs forever.