Nothing I've seen suggests brd/mch lb is stronger than caster, but maybe I'm out of date?
https://www.reddit.com/r/ffxiv/comme...l_limit_break/
Only one I can find saying other wise is here: https://www.reddit.com/r/ffxiv/comme...the_brdmch_lb/ but their evidence is "it's generally accepted" so idk what to make of that. The wiki doesn't have potencies for phys ranged lb.
Either way, as others have said, 2+ targets better for ranged/caster lb, which is pretty often. The ones that get kinda shafted are healer/tank lbs