B-Wing is the Rebel cannon truck, and looks like cannons have been improved somewhat, both Jam and Tractor now turn every hit/crit into a token. We also don't know their upgrade flexibility either - ships like the ARC will be made on their exact upgrade combos which we don't have access to.
But I suspect the primary "fix" to B-Wings will be not being grossly overcosted anymore, along with general improvements to secondary weapons.