Beast Mastery hunter

Hi,
I just started playing my 25 hunter again and was having fun, from what i have read on forums and reddit bm is the worst spec at the moment (which is fine).

I cant understand why blizzard in phase 5 have moved the beast mastery rune to the chest slot? bm rune and cobra strikes rune are both now chest runes…

The best 2 runes for BM hunters are now on the chest.

Are BM hunters secret op or is there another reason for this?