But doesn't that restrict future players from applying for a big title character in a way that they want? If they come in after an NPC sheet was accepted, they'd have to conform to that sheet. If someone nine days from now wants to play Wally West as the Flash and as part of their backstory Barry Allen died in an incident decades ago, that would conflict with the already accepted NPC sheet of a modern-day Barry. 

I get what the idea is behind this, I just personally see it bogging things down more than anything else. But that's just me.