strijder20
Wallowing in irony
Why? Stacks don't really have a relationships to cities. I think cities are more of a problem because currently they are a defensive liability rather than asset, considering that the easiest way to stack attack bonuses are city attack promotions. That might be feasible in BtS where you can abandon your first ring of cities an then mount a counterattack, but in DoC many civs only have one ring of cities.
The problem here is that cities in Civ 4 are the only strategic interest worth pursuing, as you can't occupy enemy land by standing on it alone. Therefore cities are bound to play a major part in warfare. In Civ5 cities are still the major part of warfare, but the UPT forces you to fight at least some battles outside of them.
Another workaround I have seen in other mods is 'Improved castles' (which I'm pretty sure is a mod comp), with castles forcing cultural control, damaging the enemy and improving garrisoning archers and musketeers. However, it is not the ultimate solution to the problem as long as cities remain the only assets gainable in war.
Another solution for this might be to allow you to occupy enemy land.