"Fighters (had/have/will have) a skill that reduces the FP cost of attacks. Currently everyone pays the same amount of FP for a single swing."

Fighters have one. It doesn't work, and it is too expensive. Not made a final judgement yet, but with some experience (Getting 40+ C as a Paladin, Tinker, Nightblade and Fighter), this is quite detrimental to fighters. Let's not forget what metabolism spells do (more attack than fighters, and increased FP gain).

Of course, fighters have target limb and disarm, so always wins anyway.