My personal and not-actually-relevant head canon is that the B-wing was basically a dragster- very fast, but turned for shit, so it could get inside a capital ship’s defenses and drop payload in a minimum amount of time.

(The other thing I do t get about it is why no hyperdrive ring allowing you to retain the composite beam pwnage from the Blade Wing. Maybe slap in some basic thrusters and a dumb droid pilot so it could be dropped and maneuvered while the b-wing did its smash-smash thing.)