This is something a group of my friends are all working on, and my particular task is combat. Here's what I've got so far: First, there are four types of forces: army, navy, air force, and special forces. Then, you can make as many different types of subunits as you'd like. For instance, one air force subunit might consist of griffon riders, another raptorans, and a third might be airships. Each sub unit isn't meant to represent one person, it's meant to represent a group of them. So an airship subunit might represent 5 ships, and a raptoran unit might consist of 100 raptorans. That's all just fluff, mostly. Aside from narative customization, the other reason for allowing multiple types of subunits is that they all have different costs to build, and different upkeep costs. Each subunit will have the following relevant combat stats:
Power: Default is 1.2 for special forces, 1 for others. Can be raised through research, training, etc.
Combat skill modifier: this is a player score that all units use by default, though through research, training, etc. subunits can raise their modifier. Think of it as a skill modifier in D&D, where a familiar uses its own skill ranks, or its masters, whichever is better.
Terrain: skill in various modes of terrain, which are earth, aquatic, and airborne. Defaults are are army having +2 on earth, navy +2 at sea, airborne +2 in the air, and special forces +2 everywhere. If multiple terrain types are involved, a unit's proficiency in all involved types is averaged, always rounding up. Might allow it to be raised through training and research? Thoughts?
Quantity: number of subunits
Units consist of several subunits of the same type (no mixing). So, 5 airship subunits could form one unit, 5 shadesteel golems form another unit, etc. If, for instance, you have 10 dwarf cleric subunits, you can split them into multiple smaller units, or have them in one large unit. You can have as many units participating in a battle as you'd like. Units with less than 5 subunits have their contribution to combat reduced to 80% if it's a unit of 4, 60% if it's a unit of 3, etc. This is to prevent people from creating an advantage by making lots of smaller units to add more d20 rolls and skill modifiers to their attack scores, as opposed to someone combining the exact same subunits into larger units. By the same token, a unit with 6 subunits would have its contribution raised to 120%, or a unit with 10 subunits would double its calculated effectiveness. Each unit contributes a score to a battle, and all unit scores are totaled to form a player's total attack value. Here's the formula for a unit's contribution:
((quantity+skill mod+terrain+circumstance bonus)*power*circumstance bonus+1D20)*(quantity/5)
Circumstance bonuses can occur twice, once for the addition phase, and again for the multiplication phase. The most frequent circumstance bonus will be a 1.2x multiplier to the defender on their home turf, for instance.
So, let's say Jack (with a skill mod of 4) sends the following to attacks Jill's sky fortress (air being the primary terrain type):
An army unit of 5 human warrior subunits
An airforce unit of 5 raptoran wizard subunits
This would output the following attack score:
Human warriors (army): ((5+4+0+0)*1*1+1D20)*(5/5)=(9+1d20)*1
Raptoran wizards (air force): ((5+4+2+0)*1*1+1D20)*(5/5)=(11+1d20)*1
For a total of 20+2D20
Jill (with a skill mod of 3) has the following at home to defend:
An army unit of 3 elf warriors (who have an upgraded skill mod of 4 due to their advanced weaponry)
A special forces unit of 3 super wizards
Elf warriors (army): ((3+4+0+0)*1*1.2+1D20)*(3/5)=5.04+1d20*.6
Super wizards (special forces): ((3+3+2+0)*1.2*1.2+1D20)*(3/5)=6.912+1d20*.6
For a total of 11.952+2d20*.6. The non-D20 calculations will be handled in Excel, so math slowing things down won't be a worry. People will also have the option to simply let Excel roll for them, or if the DM wants to speed things up they can also force people to let Excel handle it.
1. Are there any ways to create a metagame advantage with this system? For instance, I tried to make it so there's no incentive to split up your forces into lots of >5 units, so as to add your skill mod and extra d20 rolls additional times. The penalty to units of >5 achieves this, I think, unless I'm missing something. I then added the ability to go over 5 subunits, because theoretically it should still come out the same regardless of how many units you split your forces into. The only difference, I believe, would be that attack forces using lots of small units would have more normalized D20 statistics, simply due to the larger volume of random numbers. Is there any reason to cap the number of subunits that can be in a unit?
2. A unit's terrain, skill mod, and power modifiers can all be improved through training, research and other stuff. I figure terrain should be the least costly to improve because it's situational, skill modifier should then cost more, and power should be the most expensive. Sound fair? Should some not be upgradeable?
3. Are there any suggestions you would add for unit statistics, or ways to come up with a mortality score of some sort to determine losses for the attacker and defender in an encounter?
4. Could the formula to calculate a unit's attack power be improved in some way?