Yeah Ost is ok in teamgames and they complement OKW well but 1v1 axis is at least 80% OKW since its the only playable axis faction in 1v1 without needing to outskill our opponent considerably.
I cant exactly speak for 1v1 since I dont play it but just from playing them in team games I can see why. A lot of whats good in team games for ost (Pwefer, Brummbar, Elefant) are bad in 1v1 games.
Currenty Ostheer is just an inferiorversion to the Brits.
Bren Infantry section > Ostheer infantry
Cromwell > Panzer IV
Centaur > Ostwind
Churchill > Tiger or Panther (Apples and Oranges here, but the former is simply the better choice in most scenarios)
While I agree Ost is pretty weak I think the p4 is better than the cromwell. All the other units I agree with though.