Blackflame Friede was not exactly fair in my opinion. She's as aggressive as Champion Gundyr if not moreso, with obscenely long hit strings, and barely remains open for long enough to get even one hit in. I was lucky enough to destroy a large portion of her health bar with a lucky, timed barrage of Frayed Blade flurries, but I have little enjoyment in the cluster**** that is dealing with Blackflame Friede right after Phase 1v1 and phase Ornstein & Smough 2.0.
I suppose it is heavily subjective, but I do not find this boss fair. Gael was a much more epic and fair three-phaser that didn't toss blindside phases at you - just one health bar and a fight that evolved as his health dropped.