This will have zero effect on gameplay, or sims, or BiS lists, or priority lists, or your ability to run content. I don't think people are understanding averages here. You are not gonna do -5% all the time(we don' t even know if its +/- 5% or if the entire variance is 5% meaning it's +/- 2.5%) and you're not gonna do +5% all the time either. %5 is the extreme case not the rule. Most of them will happen in the +/- 3%, actually the majority of the hits will be between those parameters (60% of them in fact).
At the end it's all RPG flavor, it wasn't an issue before Legion and it won't be an issue in Shadowlands.
Also, please stop with the "no one asked for this". You're not making the game. At the end of the day Blizzard is the developer and if they want to do stuff like that it's their game, they don't need permission from the community to add/remove things from the game. Now, you can decide to have your opinion and not like it, but before that analyze things first before posting for something that is gonna have a net-zero effect on the game. All you're doing is acting in bad faith.