Well in the case of SR it is just a normal pug raid except that you can reserve (usually 3) items. You just look up what your BiS is and choose 3 items of highest prio. It's really not rocket science. Though even then there are plenty of pugs that are just MS > OS.
Yes, GDKP is often pay to win, but that doesn't ruin the experience of the whole game for most people. Like it has little effect on raiding guilds that do not participate in it and everyone else that doesn't do them. It's not like PVE Wrath Classic is much of competition outside of the raid dps meters you're in anyways. If for example GDKP didn't exist, it wouldn't make a difference for my personal experience, except that I could have "better"(?) bragging rights if I really cared about it.