The mortar humvees have a vulcan turret upgrade where they can take down infantry more easily and engage against aircraft, but since this is a bit of a pain for each INDIVIDUAL humvee, I think that similarly with the POW missle and Laser turret upgrade that other humvess have in the War Factory, General Alexander's War Factory could include the vulcan turret upgrade for $1000-1400.

I also think that Plasma Avengers should shoot purple plasma when they have full veterancy/experience, like that of plasma tomahawks.

The Plasma tomahawks thing is a cool design, It would fit with the shatterer too

However the mortars have their good sides as well, Unlike the other upgrades that add another weapon, the Vulcan is a sidegrade, sometimes superior to the mortar and sometimes inferior...
This is an intentional design change that I don't think will change, you play a lot vs the AI, consider some pvp...It'll make more sense there

Thing with the SWG Humvee is that it is a sidegrade. You lose range for AA. And global sidegrade is a thing that is not very popular in SWR mods. Very unlikely to happen