So the answer is fight blob with blob? Cuz the usual 3-4 rifleman build can not cut down that megablob, not to mention if the guy got Sturm officer or that blob is under command Pz4's buff, the result would not be pretty for Allied player.
Cromwell + RE speed upgrade = ultimate blob crushing, the thing is like the fastest tank in the game. If anybody complain about its accuracy, try the T-34/76 or KV-1 and you will find Cromwell's gun is like laser.
My favorite tactic for Crommie is smoke shell + speed up = middle finger to Shreck blob, Cromwell benefit greatly from aggressive gameplay.