Nah.
Go play with the M4 Calliope and you'll get the feeling for what the rockets can do. On second thought.... actually the M4 Calliope can do a LOT more than the Katyusha. The M4 will shrug off town ack, MG fire and most aircraft gun fire, still able to help level a town with its main gun, and even destroy enemy gv's. The Soviet truck that carries the katyusha would be nothing more than a tin can.
Oh... and I dare say to go learn how to effectively use the SdKfz 251. You can heave 18 of the 28cm rockets, which are far greater damage than the ketyusha can offer, and still have MG's to defend yourself with.