Wrong. OKW doesn't play defensive because doesn't need to.
All of their units are exceptionaly mobile. They just don't need to use MGs or AT guns like, for example, soviets do. They have it on infantry units (volkschreks for AT and obers for AI) which don't have drawbacks of restricted arc of fire, setup time or inability to retreat (even raketen can retreat and therefore most of the time can escape flanking).
If something went wrong you can just retreat to forward base and it won't punish you much because you can get back in fight in a matter of seconds. This have especially big influence on large maps in bigger game modes like 4v4, where retreating to base sector is very punishing.
Why play risky using team weapons that susceptible to flanking, when you can use mobile units that can flank?
1v1 is a WAY different ball game then 4v4. I have played all the game modes and I can tell you things that are a standard in team modes get you beat in 1v1. First off the attention required is a lot more, because you have to cover 3 VPs, fuel point, and muni point(need those Shreks). If you are forced to retreat on one front you can't expect an ally to immediately counter-attack and take it back, sometimes you have to give up on that side and completely refocus elsewhere.
Another point is a lone MG34 or Raketen, guarding a side, can get wiped in seconds while you are fighting on another front. Flanks are much tougher to cover in 1v1, because you don't have a team mate there. In team games OKW can play a great defensive game, because you only have to guard half or a third of the map but in 1v1 (unless you go Fortifications doc) their defensive play is much more limited due to the vulnerability of flanks and player's attention.
Also Soviets don't HAVE to play the defensive game either, Con swarms and Shocks can roll over lines of Volks with ease. Obers can shore up that line quite a bit, but one good Molotov or grenade and Obers run for the hills(due to small squad size). The Maxim, 120M, and Zis however give them much better static options for mid to late game defensive play over the MG34, ISG, and Raketen. I don't even need to mention how Riflemen can just A-Move through enemy lines.
My point is that holding VPs with defensive play as OKW is much harder than with other factions. You need to be more aggressive.