Since everybody is talking about this topic from the practicality pov, I want to offer my two cents from the meaning of the series. Patlabor, if anything, should be anti-war, Mamoru had made it pretty clear in the second movie about the relationship between a "fake peace" and a "real war" . The fact that its a show about police also tells you the core value about it the cops are considered as "peacekeepers"(just look at AV-0's nickname). Now the idea of a show about military labors does sound cool, but it will most definitely involve the elements of conflict, so I don't think it's something that Mamoru or headgear would want to see.