Weren't Shield Bearers changed from Heavy to Structural, like, three days ago? I recall Heavy being very frustrating to deal with, because while there are more ships that get a bonus against it than Structural, most of those bonuses are somewhere between 1.75 and 4. On the other hand, many bonuses against Structural are in the 10-45 range, which makes quite a difference when you're dealing with millions of hit points.
Also, Basic and Laser turrets having a bonus against the bearers is not much of a condolence, seeing as the forcefield makes everything under it immune to tractor beams, and turrets are notoriously bad at chasing things.