An mwd is only usable for transversal when kiting, not when brawling (as youre scrammed). An AB is only usable if it gives enough speed to maintain transversal. This why you dont see dual prop BS (except maybe the barg and mach), as the speed is barely usable and not worth the slot.
You can also brawl with MJD/AB, but again less usable on a battleship as youre not meeting speed requirements to pull range on targets (especially if theyre AB fit as well).