I would probably change it like this:
Both captain and lt are either 50 or 60 fuel. After you have unlocked either one, the other you did not unlock fuel cost will drop down to 10 or 20 fuel. This way you do not need to spend as much resources just to get certain unit like mg and delay major too much. Of course this would need adjusting.
That’s another solution I like. Usf is supposed to be a versatile jack of all trades faction (or
was conceptually at the very least), so having all their damn units available to them in the first place would be along those lines. You are right that it would take a lot of adjusting though.
Free lt and captain (or at the very least the second one you build) would have to be removed tho, as you would be getting them even more free at that point.
Rearranged LT tier.
-Lieutenant
-AT gun
-Mortar
-AA Halftrack.
Captain Tier
-Captain
-50 cal
-Pack Howitzer
-Stuart
Remove free Captain and Lieutenant units and adjust cost accordingly. Give Capt free bazookas to make him a dedicated AT support unit. Remove free BAR from LT and instead give him a total of two or three Thompson SMGs (or maybe Grease guns) in order to make him a dedicated assault unit. (Much like he is now, but less good at long range and no weapon slots) this will make the Captain and LT more specialist and less like rifle squads. LT gets frag because smoke grenade plus SMGs would be OP. Captain keeps smoke because he has zooks.
Each tier gets suppression, AT, anti infantry, indirect fire and a vehicle. Neither Tier has complete domination in one area but still has tools for all areas to fit your playstyle.
Major tech remains mostly unchanged except that he is now a four or five man squad that you have to purchase separately. Bigger size because you must buy separately, but higher cost. No free weapons but has two weapon slots. Basically a RE squad that has good abilities and one extra expensive Major model.
I actually really like this idea. I would say that mortar should probably stay t0 for the free smoke since it is also balanced as being an inferior mortar that’s mostly to fill in t0 gaps. Also, you forgot about the poor M20 (but I’m guessing it’d be staying in lt tier).