One could also think about creating better synergy between Penals and SU76. That way the SU76 could better fill the AT gap that SOV T1 builds have and maybe allow for build without back teching? I am not sure how this could be done though apart from some PGren-like combined arms aura. But also this would probably include major reworks since Penals and SU76 were designed to function independently of each other, plus it would not eliminate the current issues with the T70. It could somehow give the SU76 a niche again that sets it apart from the SU85.
If SU-76 will become redesigned to some kind AI unit, some ideas could be real:
About SU-76:
1. If T1 deployed Su-76 got "Break thread" ability like UKF armored car have. Then you can drop AT-satchel on stunned vehicle. Ability also become unlocked when T4 deployed or 7-th cons upgrade made in T3.
2. SU-76 will get 2 types of shells like ISU-152:
AP rounds - 140 damage, but penetration from m-42. It could easily kill any LV from front, but don't become big threat to mediums.
HE rounds - some kind of stugE - low-velocity HE shells.
3. Smoke barrage
About T-70:
2 types of shell:
1. HE rounds- decreased ROF, srapnel shots from M-42. Less damage, but bigger AOE. Small penetration. It will inficlt more bleed damage and give axis more chances to safely retreat, than current snipe shots.
2. AP rounds. Current variant, but with drastically decreased AI.
Right now T-70 overshadow SU-76 in every aspect in his timeframe. It can fight against any LV and have very potent AI with superior mobility, also have turret and armor. While SU-76 casemate TD with low armor and non-consistent AI. Only AT is far superior than T-70, but who need such AT power in this timeframe?
IF both units will be AI. But while T-70 still have more mobility and turret, SU-76 will get some utility and AT ability. Just my thoughts. But SU-76 and T-70 problems should be solved together.