Technically you don’t have a pet, so there is no “default ferocity specialization”. This talent simply provides you passives that benefit you as if you had (an upgraded) Tenacity or Cunning pet - or rather, it creates a choice to make you more survivable (preferred in PvE) or more agile (potentially worthwhile in PvP).
From what it looks like, the Hunter version of Bloodlust will be unlinked from the pet, at least for MM given they do not have a pet anymore.
There is also another change that is not in Hunter section, but in the bottom part of the original Blizzard post:
Looks like we will be able to make any pet into Ferocity, so BM/SV will be able to flavour their pet choice without worrying about BL access. I still think BL for Hunters should be a separate spell - it’s hard to have BL compete with extra defensive CD as they are just two completely different tools.