Interesting picture, it also show that USF didn't reach OKW current pick even with the OP mortar. And the pick is directly followed by a return to normal level. OKW is going up since the patch and while Ostheer is back to normal level, OKW stays over the top.
Imo, the explanation is rather simple
1- OKW has the best early game momentum allowing them to quickly win matchs. This is as per design.
2- OKW has the best late game momentym, so they have a second chance to win the match. This is also as per design.
3- OKW has an average, not better but not worst, mid game momemtum which profit from early game advantage in some cases and let OKW prepares late game advantages on the other half of cases.
On top of that, mid game momemtum is rather poor in 4vs4, what count is early and late game.
I agree with you, okw is the main reason teamgames, especially 2v2s are so hard. OKW early game with sturmpios open is too strong because on some 2v2 maps like kharkow they can block leftside fuel forever and win early game for free. OKW player does not only get an advantage but sometimes gets a free early game win. The reason is simple. In 1v1 maps are designed in such a way that you either have a one safe fuel or ammo or have 2 fuels or 2 ammos on the map. 2v2 maps have 2 fuels and 2 ammos like 1v1 maps, which means that you cant avoid early game okw power because you wont get any fuel you do so. You are forced to contest most important resources for for snowballing the game early on when its impossible for you to win against a semi-intelligent player. Even if you fuck up early-mid game you still have 5 veterany levels and heavy tanks that will help you win late game if necessary.
I think OKW elevates and carries ostheer because OST needs to survive early game when its most vulnerable. OKW takes the pressure of OST. On the other hand 3v3s and 4v4s are mainly late game oriented and both OKW and OST late are really strong af. My proposition is simple, for starters make early game equal for both sides so allies dont get muscled out from vital resources on 2v2 maps.