TBH they could have just done the same thing as they did with Sigils in 5.2 ( Upgrade the droprate significantly )
Just adding a guaranteed stone from 1 boss in SoO on top of Lei Shen and keeping the droprate as low as in 5.2/5.3 is a pain in the ass if you just started the runestone part and will make your cloak obsolete by the time you complete the thing.