Imo a "tank hunter" commander should not even have access to any sort of AI howitzer in the first place.
this
IMO, it is more of a bait for enemy to dive for.
B4 isn't a bait, B4 is a game breaking piece of crap if RNGeesus frowns upon you and can be absolutely devastating in a truly competent player's hands. Putting it in a doctrine with PTRS Cons which can lay cheap mines to ambush with grenade assault is a horrible idea.