Tyr won't be useless. Yes, ONE of her skills won't do anything against her. But she still has an invaluable debuff for Thunder teams until Mammon era.
Heck, even I can't run Thunder in this event... just not enough debuffs.
Also, Sol is Thunder's healer. So it's not like they don't have any!
Not sure if I'm running Fire for -50% Def thanks to Wrath bow, or Water for double healers. It will depend on just how much Greed hurts, and I assume it to be A LOT.