That player is not suited for mythic raiding.
that’s the not-all-that-harsh reality.
the average mythic guild had 300-400 wipes on mythic painsmith, hours per night for several weeks on end, wiping to the same boss.
what about that fits the playstyle of the “competent casual” ?
No, we do not need to neuter mythic raiding so the “competent casual” can one-shot some trivial, watered down version of it in LFR. the competent casual can do lfr, normal or heroic.
edit to add:
Wendy who only plays an hour here and there, no matter how great she might be at pwning those turtles, simply isn’t a mythic-raiding-quality of player. it take a lot more than being competent.
I’m not calling anyone bad. I’m simply pointing out that practice and repetition are a huge part of overcoming mythic bosses. you’re not getting either of those things only playing a few hours a week.