Quote Originally Posted by JNAProductions View Post
Fighters could just get an ability where they add +X to their weapon damage rolls-say, one third Fighter levels (rounding down).
They could also just get Second Wind-once per day at level one, they can regain 1d10+Fighter level HP. Get another use at level 5, then another at 10, 15, and 20.

I also would NOT add "Can only use on one weapon," without also adding something like the Warblade's Weapon Aptitude.
The math formula part is where the PB would come in. I mean sure, giving a fighter 1/3 level plus this, minus that, divided by sunspot activity or whatever is possible. But the PB would be something consistent and something there for any class, if needed. It's one thing that, for most special abilities, 5e got right, IMO.