Cortex is already very slow in play-by-post because every dice roll is opposed by another dice roll.
One thing that helps a lot with Balsera Initiative is when it doesn't matter, the player acting can declare NEXT as "any PC" or "any ally" or "any enemy". So for a Fastball Special, Colossus would roll to Create an Asset and declare Wolverine-- but if he just hits someone he can just say "whoever".
I'm also totally okay with this, but in this case I'd suggest we need to maintain some flexibility-- if Colossus declares he's throwing Wolverine, Wolverine needs to be able to say he's doing something else; if Wolverine decides he's going to be precious like Gimli, Colossus needs to be able to do something else. One advantage of pre-planning our panels like this is that if someone does temporarily drop out, we're more likely to be able to continue with their stated goals until they can step back in.
To revise my earlier suggestion, maybe the person declaring NEXT should also include a backup option, and we should each (as players) suggest our personal backup options if we can't post in a reasonable timeframe. Or maybe all of us have the default action-- if we miss the window-- of trying to reduce the Doom Pool by whatever means the Watcher deems most appropriate for the situation.