The Vrykul could always be added as a playable race for the Horde (does the alliance need a race that's basically a gigantic human). It would help the issue "ugly races" in the Horde and they are pretty much one of the last original races that qualify as playable.
Story wise, I could see a gory of vrykul splitting off from the rest and becoming somewhat of a "nicer" faction. Like the forsake and blood elves, they could need a little help to get their kingdom rolling, so they ask one of the Hordies if they could have memberships. idk, just my opinion. I say ogres and vrykul for Horde and High elves and furbolgs for the Alliance.
Class ideas:
*Warrior
*Death Knight
*Paladin
*Hunter (Owl pet)
*Monk
*Mage
*Druid (more connected to nature than humans are)
Mounts: Shoveltusk