The only one of the pet classes I really did want to see in xiv. But since we have both SMN and SCH I think another pet class will be fairly low on the priority list. I also think PUP will unfortunately be lower on the list than BST.
I think we'll see one of THF/NIN next, with musketeer/COR and then RDM being the next additions possibly also a third tanking class. After that it's probably a matter of who wins the popularity contest, my bet would be on SAM or DRK.