This and the suggestion above sound cool and interesting, it’s just not civ. I don’t think a micromanaged battle would really work in the game. That being said I think there is plenty they can do to improve battle game play. Seems like a battle overhaul would be a CivVII thing and not expansion.
To me, it just seems like what Civ has become: a hugely micromanaged battle. But it occurs across the whole world, with units in every free space at higher levels, the carpet of doom. I think the solution is a world-view that has cities, tile improvements, navies and armies visible. Armies have some limits keep them from getting too large (maintenance, attrition, maybe even food penalties to the nearest city if they get too large, with certain techs or policies that mitigate this). Invading armies can move across the map, exerting a zone of control. If they enter into another army’s zone, the fight begins and moves to a battle view, attacker moves his units first with the defender getting terrain benefits. The battle is still turn based, but it fights until one side withdraws or all units of one side are dead. You can auto play engagements with the computer or both parties agreeing.
Anyway, I agree that’s for Civ VII. I also hope Civ VII will have fewer civs but have more flexibility, like earned bonuses that unlock through the eras you can select. So there’s a base civ Britons with some basic bonuses (say maybe settlers can defend from barb attacks and ships can move +1). After a while you can fulfill requirements kind of like the Eurekas, so if you build a certain number of ships in the classical era you can pick a naval bonus and you’re England and will be able to train Longbowmen and Ships of the Line, or if you build a bunch of pastures and settle three cities on hills, you can select to be Scotland, can train Highlanders and factories are more productive. From there come choices that either reinforce your “Englishness” or “Scottishness”, or you can pick up a new traits entirely and morph into Canada, Australia, or America. Maybe you could elect leaders, like when you become America you can either be Washington and train Minutemen, or be Jefferson and have can buy tiles for way cheaper. By the time the modern game ends you’ve really passed through all the tests of time. Each civ can be replayed several times because you pick different bonus branches.
Oh, and while I’m dreaming: The best way to solve domination victory is: You have to hold every capital city, for 20 turns in a row,
in the Atomic Era. Conquer everything too soon and you’ll have loyalty issues, uprisings, civil wars, and other things to manage well into the modern era. Once you’ve taken that last capital every remaining civ is going to try to fight you to free one, which is realistic if a military despot is taking over the world. The era requirement makes the late game necessary.