I wouldn't say they are far superior, because the 76mm gets no +30% accuracy bonus like the other Sherman variants. This is especially important while beeing on the move.
Not really.
USF vehicle already have only 25% penalty on the move and on top of that the 76mm has the option of the HAVP that have higher accuracy than the vanilla Sherman.
One can always stop when shooting to avoid moving penalties.
Collision hits than are quite often in sort range further reduce the importance of the accuracy bonus.
About radio net and vet reload bonus: The other Shermans with lower RoF profit more from radio net 10% less reload in numbers because they have a longer reload.
Not when the modifier is multiplied, the effect on TTk of faster ROF bonuses are the same.
Even if was true again 76mm would profit more due to HVAP.
76mm 30% reload vet bonus is pretty much the same reload reduction as 20% reload vet bonus at E8 in numbers. When adding radio net, the E8 has the highest reload reduction in seconds of all Shermans. The MA43 and the 76mm come out quite even if you combine the boni of vet and radio net.
Have you tested this in game? because the number do not add up.
Easy8 gets *80% reload at vet 3 and should have a ROF of 5.29 without radio net.
76mm get *70% at vet 2 and should have a ROF of 3.26 and 4.52 with HVAP without radio net so I do not see how Easy8 has higher ROF. (unless something is bugged)
Combined Arms: Onlx exists at Mechanized, which has the combination of 76mm and Combined arms right now too, and at Heavy Cavalary. But at Heavy Cavalary it affects all other tanks like Jackson, Pershing or M4A3 in the same way. It is a straight buff to all units. Since it isn't exclusively to 76mm I don't see the point here.
76mm has one of the fastest firing guns and with HVAP it has excellent penetration/accuracy.
Its fun of course but what is has to do with making the 76mm available nondoc?
I have little issues of making 76mm stock and M4A3 doctrinal, I have actually suggested that myself but no in its current state. The unit is simply extremely cost efficient.