[Chazar]

I always wondered why mercenary commanders reject new troops. Why? I can see why one should not be able to separate mercenary troops, but if leadership permits, where is the reason?

I think it is just a technical glitch: mercenaries have their all their toops locked for simplicity of coding, no? If so, why is adding troops bad? Ok, you might not be able to get your troops back again, but that is true for most battles as well. Or is this in turn due to a simplification of the different routing mechanism of troops belonging to a mercenary leader?

Hopefully DomIII is better there, having a "mercenary" tag for all troops governing their behaviour (which could also be useful for troops recruitable by magic sites, summons or the gladiators). One effect means routing equals vanishing, another could be cost, a reduced priority if food is scarce and locking to a commander if assigned once.