the grenade launcher is not a bad idea. I always wanted rocket artillery, but I'll admit that I don't think we have much use for it right now.
And as much as I would love to drop all kinds of toxic stuff on their capital to show them that treaties are a good thing, spending a design on a militarily useless bomb and a revision to get droptanks on our bomber is not the way to go.
what are our problems on each front?
1) air: we dominate air to air engagements, but now they have a very significant ground AA advantage. I don't think there is much we can do for this, besides perhaps some means of nocturnal navigation. ( radar, or ebbor's directional radios)
2)Jungle:they have better coordination ( which might or might not be solved next turn, since we didn't specifically design our vehicles to hold radios and so it may not be simple to fit them), and the front is getting away from paratrooper range. small arms here and fine and so is anti tank. I think we would gain most from mobility, therefore I would propose a revision of the bomber to have drop tanks or a landing boat that can let us land behind their lines or an APC so we can escort tanks with infantry.
3) mountains: as always, anti tank. We need a revised RPG or our own recoilless rifle here. a grenade launcher may be of little help, but it isn't winning the anti tank war
4) desert: this is a rocky desert, with caves and crevices. our infantry seems to be able to clear the enclosed spaces more often than not, but their flamethrower is problematic and they are shooting down our bombers. I am a bit lost on this, but we could get some help from a grenade launcher, a better RPG and, in my opinion, a brand new tank. their increased range is often mentioned, but I believe we can do better with all the armored warfare tech we got. it would be a way to get diesel and electric turrets as well. if cliffs are not common, perhaps a rocket artillery could help.