The faction revolves around Wrathion's will to take things into his own hands in order to save Azeroth.
The faction's leader will be Wrathion, naturally.
Motivations. Wrathion has decided to stop trusting the leaders of the most important factions to do what must be done. He has decided to form an army of Azeroth's greatest heroes to help him save Azeroth from the coming of he Legion and he will not allow anyone to stand in his way.
Now, this will be a neutral faction in that it allows all races to join it regardless of their former faction. You can join the Dragonsworn via a quest chain available at maximum level. Doing so will cause your character to turn hostile to their former faction, who obviously don't like the idea of someone working against them even if it is for the greater good.
You cannot go back to your former faction unless you pay for a faction transfer. Also, all rules regarding the mailing of items between your characters if they are on different factions will still count.
Battlegrounds. It is not neccesary to revamp current bg maps to incorporate a 3 faction battle. Bgs can still take place between 2 factions at a time: alliance vs. horde, horde vs. dragonsworn, alliance vs. dragonsworn. However, it may be necesarry for faction specific structures present in a bg to be changed at the start of the bg to those of the faction's fighting. A simple matter of model changing on the go. Future bg maps may be created to add 3 faction combat from the get go.
Ex. Alterac Valley. The motivation for the alliance vs. horde battle is known. Adding dragonsworn motivation: Wrathion has learned of a cache belonging to his father, Deathwing, since the time he was posing as Lord Perenolde, located somewhere in Alterac Valley. Since neither the Frostwolf Orcs or the Stormpike dwarves would look kindly to his digging through their lands, Wrathion has sent an army to escort the team looking for the artifact.