I think they may have raised drop rates on some of the collection quests.
Lei Shen now always drops a secret of the empire or titan runestone if you're on one of those quests. (once per week of course.) And the first 8 bosses (first two wings for lfr/flex) of SoO can drop sigils of wisdom, secrets of the empire, or titan runestones if you're on the right quest.
They nerfed the world 'boss' for the end of the 5.1 part of the chain, which you have to kill after the 3k valor quest, so he can be done with 2-3 people. Or soloable if you're a good tank probably.