yep. % based class tuning murdered WoW. sucked the fun out of rotations.
we had some great posts on it during BFA pre-patch as I recall. Summarizing its effect on the game.
As soon as Blizzard gained the ability to just touch a dial (% based tuning) and roll down or roll up all of the damage on every single ability across the board, rather than individually engineer and tune aspects of a rotation or special ability or power, that was the end of traditional WoW combat experience. And that was the beginning of the "janitor era" of WoW development.
With % based tuning you don't need creativity or to create systems that are good. You can make shit systems, and then use the % based dial to "fix" it.
It enabled the McDonalds design we have today.
% based tuning is the free pass for everything possible they could do wrong. The H team janitor era was born.
the infamous wet-noodle pyroblast of BFA comes to mind. A victim of % based tuning. Every rotation became so anemic besides maybe rogues.
in case anyone doesn't know what % based tuning is, its when they take the summation of damage potential and then distribute that by % to each aspect of the rotation, like a volume dial on DPS, you just distribute then "turn down" the damage of every single ability. homogenized rotations were born this way. So a big complaint in BFA was you can do your rotation, and not feel a bang or punch. The reason was flat % based tuning. I forget what expansion it was introduced in. I know BFA is most famous for it due to the backlash it received for anemic rotations. But I would guess it's existed since after WoD.
tldr; so rather than have damage spikes, you just have a flat maintenance of dps on your rotation. every ability contributing a relatively similar impact, with no spikes or peaks like traditional WoW combat circa say WOTLK or Cata. "we'll give you these items and legenadary, but we're also going to flatten the damage spikes in your rotation by lowering some base damage and multipliers". Mundane and boring.