For me, the Vale has been my go-to for leveling carry pets. However, instead of worrying about fielding a pet with heals, I use a a STABLE full of moths (all marked as "favorites" and sorted to the top), and I just rotate in a new moth as soon as one falls to 1/2 health bar. The moths are perfect to kill the aquatics in the Vale, and hold their own with the occasional flyer add. I use the pet heal icon every time its cooldown is available, heal the whole flock of moths, and start over. Its actually kind of fun...looking at which moths last the longest, which ones kill the fastest.
I am very very sad that the Vale will not be usable for leveling after 5.4!