To be honest, I think that the DKP system works, in heroic. Anyhow, I think that the most efficient way to progress is to have loot council/EPGP. So my idea is to have the loot council for the progression/mythics(in this case), and DKP in HC. To be fair, it's a good way to gear up other people aswell in our HC runs, but when some of them get carried through some mythics bosses and get good loot that could've gone to some core raider, I feel that there's a priority issue. If we want to progress and keep the mythic raids fun, we should definitely prioritize the attending and best players. As i said though, I think that the DKP system works in HC(in this case), since a lot of the main raiders can get better gear from mythic-bosses we're killing than the HC-bosses, and if they really need gear from the HC run, they can just join there. My opinion is that the DKP system shouldn't make the HC-run the most important raid of the week, which it is at the moment. Although it's a good way to distribute gear to the ones with worse gear, that can't join mythic runs.
As for the next expansion, my opinion is the same. The loot council system is better for progression, eventhough we start in normals. Since it should go pretty quick to finish normal, the non-core raiders can join normal pretty quickly aswell, BUT when the mainraid has started HC. In that way, you will have to join normal runs to get normal-gear, and the loot council will prioritize the always attending people for HC-runs with the HC-gear, which will be better for ourselves.
Btw, I think that the council won't be egoistic and all the gear themselves, since it doesn't help the raid at all. What I think though, is that some are better than others at that task, which is why we should make 1 leader/caretaker for every class and then compare with the other classes that use the same kind of gear. This way, the person who needs the gear most, will get the right gear.
EXAMPLE: Hkan as leader for druids, Rhara for mages, Quh for hunters, Börns for palas, etc. Since we all know that they're all here to progress and not to take all the gear themselves.