Some limits on the apparatus seems unavoidable, since everything has to fit into the arena space simultaneously. Not letting MAG vault might be more of a logistics thing, though not insurmountable.
But other things about the format still seem odd. I still think it would make most sense to let countries use the athletes they want. And not to require it to be just one either. There are some pretty high quality specialists, in MAG especially, who could potentially compete in this event if countries were allowed to use multiple athletes but whose events won't match the set ones.
With the news that Andrade is probably dropping floor, and that she's interested in the mixed TF, it would be a shame if she didn't get the opportunity to compete vault and beam for Brazil because the format only allows one WAG and one MAG in the event. Hopefully it evolves by LA.