Perhaps losing the fins while keeping the front shield could be an option for the light TDs like the STUG or SU-85, maybe even the SU-100 or JP, it would create pretty interesting strategy where tanks make pretty determined flanking rushes to dislodge a TD.

i fought Bob's shielded JT before. Terrible, terrible thing. It was slow, but the way it advances inexorably towards you is terrifying!