That's what they tried when they nerfed the repair speeds and forward retreat point of the WFA and both the USF and UKF suffered the most, only when they brought the Penals to WFA level that the Soviets were actually good.
So I would say that your logic is flawed and if we're looking at the reality of things the EFA should be brought up to WFA levels instead of slapping the nerf hammer on everything else and calling it a day which as time has proven was the wrong decision.
I would also like to take the opportunity to say that I believe following the Age of Empires route and making the Armies/factions 90% similar would have been a hell of a lot easier to manage, design and balance instead of going the "unique" route ... and having a headache of tring to design and balance them.
Everybody having mainline infantry, engineers, MGs, snipers, mortars, AT guns, Medium tanks, light vehicles, rocket arty, forward retreat points, alternative repair options and so on while having different stats, different tech structures perhaps and unique units would have made them play very differently to each other, like the factions of Age of Empires, while still having the basic tools.
So in short, no, I don't agree with you that nerfing everybody down to EFA levels is the way to go, again, as time has proven, but bringing stuff up to WFA has proven to be beneficial.
You are entitled to your opinion but I have to point out some thing you got wrong, at least imo.
USF have not suffered from repair speed nerfs. They still have some of the best repair speed with crews.
The heavy supper repairing speed was simply broken, they might have overnerfed it but it used to be broken.
Part of the reason it was done was because OKW vehicles where being repaired too fast.
When they brought Penals to "WFA level" they where competently and utterly broken because they combined WFA level weapons, Flamers, ourah and Soviet level veterancy bonuses combining the best of all worlds.
Increasing the power level means that game becomes more about reaction time and less about strategic thinking, so it lose depth.
But you are still missing my point. One has to use a benchmark and balance units around that benchmark. That benchmark is grenadiers so they can not be UP, other thing are simply OP.