Well....Things like town watch or barbarian warband (or whatever EB replaces low quality militias with) should probably be zero turn because they represent a levy of conscripted townsfolk raised to deal with a particular crisis or invasion. If you could make units like town watch have zero movement allowance that might prevent the AI raising gigantic hordes of them and roaming around the map. I dont know how much of that is possible or what it would do to seige battles, but it seems reasonable to me that townsfolk would take up what arms they could find in the face of a beseiging enemy. Sortof an 'every able-bodied man able to fight' thing.

Just a suggestion...