If you can't put in the time, don't race through Mythic, it's really that simple. As someone who used to do that kind of gameplay (before Heroic become Mythic) it does really pain me to see all these people complain about shit that myself and my fellow raiders at the time knew had to be done.
Took me too long to figure that out, and I inadvertently burned some bridges before I did, which I regret.