The problem is not that stacks exist. The problem is that stacks are difficult to manage.
Well said!
1) Armies
Units grouped together should create super units, not loose collections
of individual units. I propose that in combat, each unit will take a turn,
depending on their movement, morale, and type. Each combat turn, a
unit will deal and receive damage. Then the next unit in the army will
fight 1 round.
This reminds me of the Hearts of Iron system. To apply it on to Civ4 could mean something like this:
You build Divisions of Axes, Swords and Cats as you would now. But you also need to build a Commander. Then you assign multiple divisions to the Commander. Assigned divisions loose 20% strength each time they get assigned, and then has to "heal back" to full strength. From here on, you control the whole Command instead of the divisions under it. Of course you can detach the divisions, but that division will suffer a strength penalty if it is on the offense.
Each Commander has a rank. Low ranking commanders can only command 4 divisions. Over-commanding is allowed, but all units under that command suffer -10% strength penalty. With experience, the Commander levels up and is able to command more divisions. Promotions are assigned to the Commander instead of the individual divisions. If a special (and expensive) unit called an HQ unit is present in the tile or adjacent tile, then the command limit for that battle is +100%.
Combat is between two tiles, not two Commands. When one Commander initiates attack on another tile, all units in both tiles participate at the same time in the battle. The highest ranking Commander on each side sets the side's command limit and all units are still subject to over-command penalty even if they are each assigned to a commander of appropriate rank.
This will effectively eliminate multiple Commanders forming huge stacks. You can still swap out injured Commands and reinforce with fresh Commands, but that'll be the next turn you attack. Also, "combined arms" actually can mean something with this kind of combat, instead of the very much simplified countering units system. For example infantry with cats gets +10% city attack, or infantry with mounted units gets +10% critical hit.
One can also factor in a flanking bonus if you have friendly Commands able to participate in the attack from another tile. Something like that.
Now during each round in the combat, each division takes RNG roll and picks one enemy division and takes a whack. Each whack takes RNG roll to determine hit/miss as it is in Civ4 now. Repeat until some condition is met or maybe even make it happen real time and player can decide to withdraw from the attack or withdraw from the defense (meaning the defenders give up that tile). Siege weapon can be used to modify other division strength when not attacking cities, and when attacking cities, used to reduce city defense over a period of time (during which the combat between other units are already happening).
You can put in a promotion that allows a Command to have ZOC or something. Don't know how that would work out. Or make it a special unit like a Scout attached to a Command lets the Command enjoy a ZOC.
Random thoughts.
Edit: People will still want and find ways to bring huge stacks, though. You need to cut it at the production source. Use maintenance or a hard/soft/moving cap to the number of divisions/commands a country can have. But this whole system is making combat even more complicated.
