This thread is about 120mm being able to retreat at one man, whereas other mortars cannot. That's it.
If that's all there is to discuss, I don't think there's much to really say. I personally think it's fine as is, but those who think the mortar is OP will of course want it changed.
Yes it can retreat with 1 man while the others can't, but it has 3 disadvantages that the others don't: it's doctrinal, it costs 360 manpower, and it costs a whopping 12 population - which is twice as much as the others (even the mortar halftrack only costs 6 population!). The bottom line is that the 120 mm mortar is different than the others in many ways, so why get so hung up on this particular difference?
I keep hearing the argument that it's unreasonable for one man to carry that mortar - but to fix that "problem" they would actually need to change the animation itself. But moreover, why should we care about soldiers lifting more than is realistically possible? If we did, the AT guns would be damn near immobile.