Setting aside civ7 featuring a combat system more similar to Humankind for a minute, support units as a system are a fantastic addition the to series. It's just that it was never fleshed out.
Many units should be support units rather than standalone. Personally, I think a combination of support units and the "tech upgrades" of the GDR could make a combat system people would be fanatically addicted to. (Trivial example: ironworking boosting the combat ability of ancient era units like spearmen, while also unlocking classical units. Might even be accompanied by a graphical change.)
The structure is all there, it's just not used.
I personally think that support units should basically be combat utility that you add to actual combat units to mix things up. We already have siege equipment, but I would like to see, for example, anti tank guns being something you might attached to infantry to give them a defensive bonus vs tanks. Whereas, say, a machine gun support unit might assist when fighting other infantry.
Personally, I would scrap the promotion system we have now in favor of adding those things via support, tech, or some other system, and just letting "promotions" grant +1 combat strength per level. Call it veterancy, idk. But the promo system we have been slowing inheriting from civ4 kept the devs from being willing to merge, trim, and create new unit lines as needed, and that really messes up game balance. Helicopters really shouldn't have the same combat class as horsemen. Archers shouldn't end up as machine guns. They should be folded into gunpowder units at riflemen. Etc.
Check to all.
The current Promotion System is a combination of technical upgrades, tactical changes, and just plain silly words thrown in to mean things they never meant originally. It needs to be separated into Technical (technology OR Civic Upgrades) and real Promotions wich reflect the effects of Experience and professionalism.
ALL military Units throughout history include 'Support' - non-combat or semi-combat people tagging along to keep the combat troops capable of fighting. The average Hoplite army of Classical Greece included 1 - 3 servants for each Hoplite, carrying his shield and armor before they got to the battlefield, cooking meals, carrying food, and looting the enemy dead if things go well. Chinese Classical/Medieval Armies from the few decent statistics we have seem to have also averaged 2 - 3 'support' non-combatants for every Combatant, even when the combatants were conscripted peasants. I've posted before, since World War Two (game Modern/Atomic Eras) every soldier in the front line or combat support units also has 2 - 6 non-combatants in uniform hauling supplies, ammunition, driving trucks and wagons, cooking rations, writing press releases. There is always a 'tail' to the combat teeth.
The trick is to make the basic Support invisible - it's simply an extra cost built in to each Unit, which allows you to move that unit normally. The extra Support would be all the extras required to, say, move a Unit through the desert, or supply it across the sea, or provide the hundreds of tons of ammunition and fuel required by modern (20th century) militaries anywhere, and investing in it would be, to some extent, your decision as a Gamer/Personification of the Civ: don't invest, and you end up like Germany, barely able to project military power more than 500 kilometers outside of Germany. Put a mass of resources into Support, and like the US military, you can put a million men clear across the Pacific Ocean complete with fuel, food, ammunition, and lavish air and naval support.
- Or send a Roman Army to Africa to finish off Carthage: it's the same in every Era, just different Technologies and capabilities available.
Combat Support is things like
Carroballistae (small portable catapults) added to Roman Legions in the Empire, or antitank guns. antiaircraft guns, combat engineers in modern Infantry or Tank/Armored Divisions, or 'battalion guns' - light artillery added to musket-armed infantry Units in the 18th century. Some of those can simply be technical Upgrades, others are more complicated, because there were also Brigade-sized Units of antitank or antiaircraft guns used to Mass their effects where needed to counteract massed air or tank attacks. I think these will have to be thought out on a case-by-case basis, and some of them will probably wind up as Unique attributes for certain Units in certain Civs.
Technical Upgrades I've been beating the drum for in other Threads, like
Unit Ideas for Civ VII. From that Thread, here is a partial list of potential Technical Upgrades for ground units from Ancient to (approximately) Industrial Eras and their base effects:
Light throwing spears** - Has 1-tile Ranged attack
Light shields* - Bonus against Ranged attack
Secondary Melee Weapon (sidearm) - Bonus Melee Combat Strength
Metal weighted Weapons - Bonus Melee Combat Strength
Leather/cloth Body Armor* - Bonus against Melee attack
Lead Sling Shot - Bonus Ranged attack against Ranged or Scout Units
Metal Body Armor* - Bonus Melee Combat Strength, Bonus against Ranged attacks
Composite Bows* - Bonus Ranged attack
Heavy Shields* - Bonus against Ranged and Melee attack
Metal Tired Wheels - Bonus Tactical Speed for any Chariots, additional Support from Wagons
Heavy Spear/Lance* - Bonus Melee Attack when Charging
Heavy Throwing Weapon** - Penalty to opposing Melee Combat Factor
Torsion Propelled - Bonus Catapult Ranged factors
Cart-Mounting* - Bonus Movement for Catapults
Articulated Plate Armor* - Bonus against Melee and Ranged attacks
Halberds* - Bonus against Mounted or Infantry in Melee
Iron Cannon Balls - Bonus against Fortifications for Bombards or Field Cannon
Corned Powder - Bonus Combat/Ranged Factor for all Gunpowder units
Elevating Screw - Bonus Ranged Factor for Field Cannon
Cannister - Bonus against Melee attack for Field Cannon, Howitzers
Precision Bored Barrels - Bonus Combat Factor for Gunpowder Units
Manual of Arms Drill - Increased effectiveness of Amateur or Professional Gunpowder Units
Mixed Formations** - Allows mixing of Units and ‘converged’ factors and effects.
Volley Fire** - Increased Ranged Factor
Rifled Carbines* - Increased Combat Factors for Mounted Units
** = Could require a new animation
* = could be shown by a new Skin: brown or cloth colored for leather/cloth armor, bronze, gray, or shiny for bronze or iron/steel armor, etc, or by an additional Graphic irtem: shields, carts, different weapons.
Most of these would require a new Technology to implement, in some cases (shields, body armor) they could apply to numerous different units, in other cases (cart-mounting for catapults, Lead Shot strictly for Slingers) they are specific to a single Unit type.
Otherwise, however, I'm really neutral about the very existence of strategic resources in general, except coal, oil and uranium. Horses weren't really that rare for the scale of this game to completely disallow cavalry for any nation in Eurasia and northern half of Africa (they weren't present in the rest of the world for 'unfair' reasons that shouldn't be in the game anyway). Iron was quite common metal almost everywhere (I don't remember why it wasn't used in Americas). Niter/saltpeter are especially stupid strategic resources, I have never ever met with the notion of 'and then country couldn't have more guns because of lack of niter' outside this game. Aluminium I don't care about at all. And coal, oil and uranium all arrive in the similar time period, so you could just rebrand strategic resources into something you only need since industrial era, without OCD need to have some nonsensical strategic resource for every era and every unit.
