A heavy tank, that is the price of a medium tank and requires a doctrine to counter. Great.
first, it depends on how you define medium and heavy tank. the game considers the V and comet medium tanks and the kv-1/2/8 and churchill heavies. the kvs have 800 hp... so yes, technically the kv-1/2/8 and churchill are cheaper than medium tanks but certain medium tanks also cost more than heavies. if you talk about the standard, "t3" mediums though the most expensive is the pIV which is 125 fuel and so the churchill is actually 25 fuel more expensive. if you compare the churchill to the V/comet the ONLY advantage the churchill has over the other two is the health and regardless of whether or not it has that health the other two will beat it anyway. also, requiring a doctrine to counter the churchill is just you not being a good enough player; everyone get's the doctrines with the V and jpIV.
They'd probably be fine if grenade was removed. The ability to counter their counter is just poor design. Also the croc is still ridiculous and definitely still does more flame damage than the Hetzer, despite flame damage apparently bring "normalised". No other faction can be so frivolous without fear of punishment with their armour
AT guns counter the churchill hard as long as they stay out of range, which is why they have 60 range and the churchill has 40 range on the main gun and 10(?) on the grenande. you also have snares (mines as OKW and, ignoring tellers, pfausts as OKH) to keep the churchill away from your single AT gun that you really should have multiple of because one AT gun seldom counters anything by itself as pretty much any tank can drive through the ark from the front.