The thing about USF is that the LT costs enough fuel that it often creates and either/or situation as far as the captain tier is concerned.
If the LT was made cheap fuel-wise, it would for sure be used more. It would certainly help break the monotony of rifles in the earlier game. And though I do like AT guns arriving later rather than sooner, we already have t0 raketens and ZiS readily available so that's kind of moot.
But I'm also crazy and think that only the Lieutenant should have smoke grenades, without needing grenades researched.

The M20 would be great to see having a window of effectiveness, especially since the 222 has enjoyed some much needed buffs. (I still think 300 health was at least 20 health too much. It needed armor, at least as an upgrade.) Only question is how it would roll with OKW, especially if we consider the notion of no volk schrecks.