I also wonder who's great idea it was to make two parts of the same quest line nearly identical, only that the quest item is named differently and only drops from half the bosses.... Dont be too creative now... /sarcasm
Anyways, it can take a ridiculously long time to collect these. Im still only collecting SotE and i only have 11 from 4 weeks, so im counting it taking 4 more weeks untill m done (3 if im lucky), this is really way too excessive to spend 8 weeks on a single step, not to mention the Runestones probably will take just as long if not even longer.
What i propose is a soft fix, to make SotE a 100% drop from every "end" boss in the LFR wings (same translated to normal and hc ofcourse) while keeping the small chance as there is now from the other bosses. Similarly with Runetones, make them a 100% drop from Dark animus also and let the chance remain from the other 4. This way it would take 5 and 6 weeks maxmimum, which is already a really long time.
As it is now, its simply ridiculous. Especially when there is no other reason to go through the raids every week.