the ‘Suggested Topics’ does look like others have come up with similar ideas.
like this from 2015
https://www.axisandallies.org/forums/topic/26036/simultaneous-play-in-opposite-theaters/11
I have not played the versions with more than 5 powers, but I do think the basic idea can work to reduce the number of turns in a round. by changing the turn order.
Implement after the 1st round or 2, to keep positioning balanced.
Depending on the balance, some small advantage for the power who gets skipped.
Then powers on the same side who have consecutive turns may all go together as long as you break the combat moves along the original order (from the perspective of the attacked)
Breaking the combat into multiple rounds does seem to be the organizationally new thing.
(or at least I haven’t found someone say it that way on this site yet)