Yeah it's doable, we just did it with a social raiding guild (read: non try hard at all) after 3 tries.
Boils down to this: 2 tanks tank Gluth at the door (other side of the room). 2 CC AoE take care of the zombies, at decimate all DPS switch to zombies so they die before they can reach him. Frost mage and prot warrior for insane CC worked wonders. With this setup just two zombies got to him, which isn't that bad since they heal like 8% per zombie.
Also heroism on start so you can take him down asap, gets good DPS in when there aren't many zombies around.