Yeah the Raketen needs a faster set up time, got absolutely destroyed by multiple USF WC51 car rush in the beta in 1v1. In fact I think it was against Hon3ynuts, wasn't it Hon3ynuts? Multiple scout car opening for either faction is strong against OKW, especially WC51 into Stuart, that was such an ass wuppin.
If you're facing multiple vehicles, you should have multiple AT, don't expect a single AT source to handle everything.
Combine, either with shreck/2nd werfer or with mines to protect flanks/frontal rush.
Also, WC51 is pretty huge investment given you are getting a weaker version of soviet M3 and need to pay 25% more, rifles being more expensive then volks also guarantees that you will always outnumber USF player as both, wehr and okw and the doctrine doesn't really have anything else going for it.