Yes it is, I'm also part of the top150 2vs2 with USF, and top 50 in 4vs4 so I know well what people I'm facing are doing in those modes.
After a month of abusing ISG spam to win, many OKW players are just going back to their real rank position. But building Obers and combining and microing them with Volks and sturms? Too hard, if it doesn't work in a blob that requires too much micro!
Majority of Ostheer players can't do anything else than gren spam or ostruppen spam or pzgren spam, same at top150 2vs2 or top50 4vs4. Mixing them, using their combined force? noooo too hard!!! too much micro skill requirement.
Ostheer is probably the faction providing the most variety but you never see it in game. There is always the need of spamming one unit and whining in the fora if this unit isn't enough OP.
If its so easy to win with OKW & OST in 2vs2 then please go ahead, get a TOP place after playing 10 games with those factions in that mode, since you haven't done that yet, because this thread is about 2vs2 balance. Nobody cares for 4vs4 ranks as they are easy to achieve.
OKW/Ostheer winrates were in the same state before the ISG nerf on top, its not like the plummet, they stay they way they were/are.