Regarding movement I was thinking about some changes, what if:
* Increase the number of tiles
* Variable unit size. Scout takes up one square. Military unit four squares. Army of military stacked units take up 8-15 squares.
* Variable unit speed. Scout moves many tiles a turn. Military unit average. Army a few squares every turn.
* Variable unit ZOC. Army has huge ZOC.
* Cities are spread over several squares (like Old World)
Don´t know if it would create realistic movement, but maybe.
I'd like to keep all units in a single tile, as well as all armies until, possibly, the Mass Armies of the 20th century.
Unit speed across the map can be modified heavily by both the units size and capabilities and the unit's requirements in food and sustainment to move at all.
For example:
An early Scout unit, I've always thought, represents at most a company of lightly-equipped, lightly-armed men moving fast to search out the country. In the game, they can both have a higher movement rate per turn, but also be exempt from any supply requirements - they can live off the land better than anyone, and even later don't plan to get into any major firefights and require a lot of ammunition resupply.
Any military unit represents, at least, several hundred, thousand, or even 10s of thousands of men. They require a lot of food, and so do their horses, and even when the horses are retired, the vehicles require even vaster quantitied of fuel, spare parts, lubricants, etc. A late-game infantry division, even if the infantry are marching on foot, requires several hundred vehicles to move its artillery, signals, supplies, and also requires several hundred tons of supplies Every Day to keep moving. They cannot 'live off the land' - even if they are moving through extremely rich agricultural country at the right time of the year, food is less than 10% of their supply requirements by weight, and the land will not supply ammunition, fuel, and spare parts. That means any military unit not part of the 'reconnaissance line' requires Supply, a supply line of some kind, and so to an extent is tied to that supply line rather than free to gallop off anywhere it wants. Even if they had the same Movement Rate in tiles/turn, they could not get from Point A to Point Z as fast as the Scouts. In fact, they will not usually have the same movement rte as the scouts, unless they are a completely motorized unit, and then they will be tied even more securely to a supply line delivering fuel.
And note that none of this applies in your own territory, where usually you will be within a short distance of the neaerst friendly city and infrastructure: units and armies will, therefore, automatically slow down in enemy territory, even if unopposed by an enemy army or units.
The best thing about implementing this kind of Variable Movement Rate Based on Logistics in a computer game is that the gamer does not have to calculate all the supply factors every tile and turn - the computer can do all that, and even give you a chart-type display of what is slowing your movement down: terrain, lack of roads, lack of supplies, weather, Friction, etc. If you are in a hurry, you click on the tile that is your objective, the game tells you how many turns it will take to get there, you drop the Bombard out of your army stack, and that speeds up the movement of the rest of the army enough to reach the 'target' faster. Of course, without siege equipment you may not be able to do much to it when you reach it, but that's the kind of decision generals make IRL and the kind of consequences real armies have to face . . .
Variable unit/army ZOC definitely.
ZOC to me represents the ability to inhibit enemy acyions at a distance, which means either very long range surveillance and attack or very mobile units that can intercept enemy movement and action.
Specifically, Mobile Units - scouts, light cavalry, helicopters, armored cars, etc would give your Army stack a larger ZOC. Modern Artillery with satellite and drone surveillance available - an Enormous ZOC, because anything they can spot, they can kill, which tends to discourage movement anywhere they can reach. Same dynamic applies to Aircraft, and how they operate in the game needs to change dramatically, because the most lucrative combat mission as far as influencing the battlefield was found to be (in World War Two) intercepting reserves, troops and supplies moving up to the front, not attacking the front-line positions and units. In other words, an Aerial ZOC hindering movement behind the enemy front.