Every faction has something to counter enemy's blob by arty or by very good and const AI vehicles.
OST: PzWefer, Tiger, Tiger Ace, Brummbar, even LeFH.
SU: Katyusha, IS2, ISU152, KV2, KV8, demos
OKW: Sturmtiger, KT, Stuka, Schwerer (
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USF: Priest, Calliope, Pack howies, HE Sherman, Scott, Pershing, Bulldozer, demos.
Brits: shit Sexton, immobile mortars, no tank with potential of Tigers or ISU. The only thing which comes to my mind is AVRE but it's very situational. There is also Croc but it's not like arty or vehicles with big AoE, it's working on a different level.
Firefly - great AT.
Comet - Good generalist but it's not like Tigers in terms of AI.
Churchill - sponge.
Non doc arty?
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Doc arty?
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There is no unit which can punish blobs by wiping them like arty or keep bleeding them like Tigers, ISU, KVs, Pershing etc.