How about pathfinder sniper rifle 2->1 and some manpower sale?
That was not done so units could beat Pathfinders by closing the distance where the unit is relatively weak. Despite having paratrooper carbines, they lose those first when models are dropped, allowing them to be countered by basic infantry early game.
Finally many USF units are extremely cost efficient and only see little action due to tech restriction removing those restrictions would mean re-balancing these units.
Only the M8A1 and M36 in the core is what I call incredibly cost-effective, but that is a different discussion. And M36 Jacksons have to be as USF has only 1 true TD in its core and the M10 will never be stock.
But switching the AAHT and the Stuart just serves to reverse the very goals you're purportedly seeking. It'll always be LT first, with a decision to rush a stuart or go for an ATG.
Worst scenario we go back to where the units are paced in the tech. We are keeping an eye on the Stuart rush with LT backing that is backed by the .50cal.
I know it can be an issue, we had the discussion behind the background how these units would be used. Captain we knew won't be the main pick for the majority, but would still be used for a more defensive and attritional gameplay.
There is also the issue Captain would not be picked in general even if it kept its Stuart as you can back-tech to ATGs to deal with vehicles and protect the AA HT with another squad to support. Stuart is only considered decent enough to do it job, mainly against other lights particularly.