Well it might not be flying. Alex west's thoughts:
Looking at the cards available, I wouldn't be surprised at all to see a viable Anvil Throne soldier book or any Warlock demon book do well. The "Fast" Battle Order for the soldiers, and the teleport power on Wildfire Imp both get the creatures where they need to be, while both Altar of Carnage and Pentagram offer powerful economic engines to support them.
Heck, even a Wizard's Blue Gremlins have the sort of mobility I want from a swarm creature, and Gate to Voltari isn't too shabby at mana generation. Though, Wizard is slightly lacking in the mass buffs I want for my swarm. I guess everyone has access to Marked for Death, but no other mass buffs like Armory or Bloodfire Helmet make it a little harder. On the other hand, the little buggers are pretty hard to kill due to their dodge and point of armor, so that's something.
Not sure how the pvs and lg cards affect this.