I'd venture to say "specialty" ships.
Even then, in 90% of the cases (carriers, droners, etc.) it's more due to a lack of "appropriate" (read SFC-itized SFB canon) BPV adjustments more than an inherent issue with the ship's themselves. One bright spot of LB5 was that, after some of the DIP BPV adjustments were applied, the droners / carriers felt a lot more balanced than usual, ie, a CL-carrier with a half-dozen or so fighters was a match for a CB / BCH sized ship, and it advertized itself as a bigger ship throughout the battle.