The "mercenary" recruitment model
In a nutshell:
1. Do away with the MIC system.
2. Use the mercenary system to model the raising of an army:
a) units available only in appropriate provinces (or regions*);
b) faction-specific units hireable only by that faction;
c) appropriate costing for the unit-type**;
d) unit availability that reflects traditional army composition and historical manpower reserves.
* I don't know whether mercenary recruitment pools can overlap, but it'd be great if they could. You could have one pool for the whole of Italy (which would contain regular troops), and another for each of the provinces within it (which would contain levies).
**
Levies would be very cheap to raise but ruinously expensive to maintain (to reflect damage to crops, etc). You might need to script the disbanding of levies for the AI.
Regular soldiers would have a lower ongoing cost, but a higher initial one (to reflect training, etc).
Mercenaries would probably fall in-between these two extremes.
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