That does need a bunch of asumptions of how "hostility during non-war" works. Also Civ is a lot less focussed on Warfare then any AoW game ever was. For AoW Unit design and even manual combats are a core mechanic.
It would certainly help to speed up turns while at peace/preparing for war.
Civ being less focused on warfare and still the simultaneous turns mode turns its wars into hectic clickfest is probably a lot worse in AoW, especially involving the Adjacent Hex Rule. Sequential/classic turns mode does not have those issues but being much more slower might not be suitable for most online games. Having a Hybrid mode would be very good, but, yeah, probably in the next AoW after Planetfall.
I'm not sure if 'Everyone Pause whenever Tactical Combat happens' will ever be eliminated, although some rules could be implemented for multiple TacCombs to happen at once, it's probably something to do with the engine being unable to process them simultaneously. That's probably why the Total War series' campaign multiplayer is still limited to two players.