The trucks are a non issue. If you loose control of the map you're going to have to expect some sort of punishment. The trick on most maps is to manoeuvre around them, build artillery and shell them.
It's always a good idea to take at least on of the artillery doctrine commanders, preferably a self propelled artillery piece and then use it to punish arrogant OKW players.
I mean hell, watch any of Fortune's games, he uses artillery to punish OKW players for building IN THEIR OWN BASE. Great example in the replay bellow:
http://www.coh2.org/replay/45788/dotdotdot-v-fortune
Seriously the only building that OKW have that should arguably be changed is the Shwer but still even then it's not impossible to kill. A well placed AT gun can eliminate it for gods sake.
And before you say anything, no I'm not a Wherboo I'm actually a USF Fanboi.