well there are a few problems; they're more expensive than normal troops, and we don't have the required MICs to recruit them in many cities (I think only Roma can recruit them, and we can't even have access to the whole range of Italic troops).

I think the only possibility of that is for a "Italic provincial legion", where some very influential provincial dictator persuades the CoL to recruit him a provincial army composed of Italic allies, then it could be role-played like the Italics are not satisfied with the senate or something, so they help that provincial dictator seize power.