In theory, the rules could be adapted to a modern setting. However, they are designed for a medieval setting and that's the way I'd like to try them out first. Magic is not strictly a part of them either, however, a squad of hedge wizards can use the same rules as a group armed with heavy missile weapons. If teams of wizards were chanting to make a protective wall around a unit, that can count as increasing the unit's armour quality. And so on.
Kingdoms themselves will be designed by me, but will be large enough to support the army. For example, for every squad of mounted troops your kingdom will have fields, whereas flying mounts come from mountain regions. Units with better equipment come from towns or castles, whereas common fighters hail from villages. The armies, for now, determine what your realm looks like.
And this you can design yourself.
Of course, this may be a little hard without pointers. You don't want to create a force only to find out it's extremely small or way too large, so you'll need something to go by.
I'm not really worried about sizes yet, as I expect smaller forces will ally to fight off a larger foe, compensating in that way. New armies will also be subject to stricter rules, but I will first need a couple of nations to act as the main realms so I have a framework to build around.
The small army in my first post is just that. This is about the size you can expect from the smaller nations new to the world.
Basically, you can go about army creation by making one unit at a time.
Units consist of anything between 1 and 5 squads. This is the equivalent of 100-500 men. There's a point-based system which will mean that, if you are working towards a points limit, you can have either more lesser troops, or fewer with more and better equipment.
The units each have armour classed from light to medium to heavy, and of a quality ranging from standard to good to exceptional. The men can also take a shield with them. Armour can have strengths or weaknesses against different types of weapon.
Heavier armour makes units slower and lets them fight after more lightly armoured units strike.
Weapons come in short, medium and long range categories, and have the same standard-good-exceptional quality. They can be ranged weapons or melee weapons, and units can carry several different ones. They can also wield several different ones at any one time. Weapons come in blunt, piercing and slashing types, or any combinations of two of those. Some armour types are especially sensitive to certain weapon types.
On a charge, units with longer ranged weapons strike before those with shorter weapons do, even if they are more lightly armoured.
Units can be mounted, and mounts can be killed. Mounts come in fast and very fast types, and may also fly fast or very fast. Because they can be killed, they have their own defense rating, which depends on the kind of animal you are riding. Elephants will be more resilent to damage than horses, for example, although barding may help the horses survive a bit longer.
Aside from that, I may grant units attack or defense bonusses depending on a unit's special abilities. Dragonriders will get an attack boost, for example, as their mounts fight as well. Units being charged by dragonriders while hiding in the forest will get advantages in their fight as well, because of the trouble dragons will have flying around in there.
The above is an indication of what I need to know for each unit, however, you can also just tell me you want crossbowmen with extra shortswords and I can work out the details myself. For more unique units I may need some extra information.
So far for individual units, but how large should the army be, I hear you say. Well, very roughly and assuming you want a regular army without anything special, representing an equally regular kingdom, you are at four times the size of the 'small army'. Remember that you'll have to split your force up into smaller ones if you want to be able to attack AND defend succesfully.
Four times the size would mean you have no flying units, some 1600 horses, 1200 men with exceptional equipment, some 2800 men with good equipment and about 4800 troops with standard equipment. For the initial armies you can take whatever you like, with this as guideline. Of course you can have some flyers as well, or a lot of them if you want to live in an especially mountainous region. If you have a theme to work around, it'll be a lot easier but you'll likely have less balance.
I'd like to see some lists, either posted or PMmed, and if nessecary I'll give advise on things to change. I wish I knew exactly how it'd work out, but I don't. Just try something and we'll see how it fits in.
And by the way, until we get started, everyone can be in control of a 'large' nation. The smaller ones are for the late joiners, although you can of course opt to have a smaller army and nation just by selecting a smaller force
Cous found the first flaw in the plan yesterday when he talked of regular units with wings rather than winged mounts, but I've patched that, so you can pick avariel if you like