I have found that in WoD zones I cannot interact with the pets - what I mean is, in all other zones I used the common technique of clicking to check for a rare, forfeit, kill (to force a respawn), and so on.
Now I cannot kill the pet (or mark it) - is that a bug?
Second, I also used a technique to 'pull' a pet from a place where it could not be battled. For example, I found a Mudback Calf on the floor of a pool and could not find a place that would allow combat. I used to be able to 'taunt' a pet so that it would 'attack' me, then 'pull' it to a place that would allow combat.
But that is not possible anymore (as far as I can tell), so when pets are spawned at unusable locations they cannot be battled.