Zul'Farrak now has an uninstanced area where you can easily get in through flying or other means. In the temple area, where the Sandfury Executioner would be in the instanced version, there is a massive number of dancing trolls. You can collect these trolls up and AoE them down. Each one drops items, and presumably gives experience. There are at least 50, easily more. They respawn within a minute. These trolls give exp for characters below low-50s, approximately 52.
Edit: There's another place in Swamp of Sorrows for Horde only: Marshtide Watch. There's a huge cluster of Marshtide Footmen standing in a square presided over by a 15k hp NPC. Fly in, AoE them all down, and loot them for runecloth. They don't drop a great deal of it, but they drop some and this might give a nice chunk of exp as well for any low level characters in your group.