If one unit is severly overpriced for what it can do, it is a balance issue, regardless if other units are priced decently. And if a large portion of your game's content has that OP/UP status, it is fair to say that the game itself is not balanced.
Otherwise we'd not have "balance" discussions but "diversity" discussions for years now, but this is just a change of phrasing with no benefit.
If unit is "severely overpriced" it will not be used and that will not effect faction balance. That is balance issue of the unit and not a balance issue of the faction/game.
Win ration do not take into account how many different types of units are being used.
If the game is balance playing meta it is balanced, it might be boring but it still balanced...
I don't have a pony in this race, I don't care which patch was the biggest fuck up in CoH2. The stats you show though clearly indicate that ouraa flamer Penals were not the biggest issue since USF does not have access to them.
Which patch was the worse that is not really to relevant to my point either.
(As for USF having higher win rates that was probably due to bugged and the completely broken USF mortar at the time but at least we did have to wait 6 month for that to get fixed)
My point is that claim Relic did everything "wrong" on their own and community did everything "right" is false.
And Relic did not work on their own they had the help of people like helping hans, zarok, Big rat, Luvnest and other...(forgive if I got any name wrong and for not remembering all names)