Not really. Pick whatever has whatever you like.
I picked Maldraxxus on my first 60 because I wanted an abomination friend for him. Beyond that I sent my next 3 guys, 2 paladins and a rogue to Revendreth, Bastion and Ardenweald respctively because I wanted to see those stories and collect all the mounts and pets.
Beyond that the balance of my guys will go to the 4 covens randomly pretty much to get the transmogs and funnel anima to my first 4 so they can max out their halls.
Only character I specifically picked a coven for was my hunter in Ardenweald. I really want that alpaca form to go with his dual alpaca pets.