I had the biggest slump from the Beasts of Fable bags lately (getting nothing but food and a trash item for about a week) but still regularly getting stones and Pandaren Spirits from the other dailies. I'd put it down to RNG just hating you.
Got a few today (one magic and one beast, I think). My luck with them has been rather poor the past week, but that could just be because I haven't done a lot of wild battling. The trainers alone are a far too small sample size to really say much.