I'm not a very good gamer. There, I said it. I get disoriented easily. I get jumpy, trigger-happy, and my aim goes to shit. Alternatively, I am overly cautious, a sensible habit given my inability to walk into a crowd of enemies and score a dozen headshots in a second. But then if there is a timer of any sort, oh then that's trouble indeed.
I'm the reason games have difficulty sliders.
Why do online games so rarely have difficulty sliders?
There's an obvious case for not having them in PvP: that is, that they make it unbalanced. Skill falls out. That wouldn't be very good at all. It's the same as why no one likes playing against cheaters. Uh... pay no attention to the gear behind the curtain.
But why not raids? If I can't kill Lich King on normal, why not have an option to dial back the growth rate of defile? Lower the health or speed of valkyr? Why not?