I think a really interesting final crisis would be to have the superhero, super villain, or sidekick like myself lose their power for a brief time. I like the idea of their power only being missing or lost for a brief time that way it is not as if they just turn normal and change their whole lifestyle. Instead it is a huge adaption in a small amount of time. I think it could be really interesting for our characters to have to continue fighting crime, or causing crime without theirs powers, until they return. And for a super human what is a bigger crisis then losing what makes you super?
For example my character Little Brain can read minds. So for some reason there is a block in his mind reading abilities for a few days, but a villain is on the loose. He can not take a day off from saving lives so what can he change, adapt, do to save the city? Maybe he uses his extensive knowledge to get an edge on the villain, maybe he uses his normality to sneak up on the evil guy. What do they do to be super when they are really just normal! Plus then there is a super come back story to end it, and who does not love a come back story?