The fact we've had so many mummies, powerhouses or not, leads me to believe at least one or two of them should have held out for lich.

It doesn't always work out and yes, they'd have to wait for Uniron to approve/compile their own personal quest, but I really do think people are giving up too quickly these days. He's a lot of things and RL is keeping him busy but there's nothing out there suggesting that if the rest of the pantheon was like, "Yo this guy seems legit could you spend an hour inputting his quest," that he wouldn't do it.