I have the same thing going on. The only reason I can think of is that my horde toon is higher level (also more time played) than my alliance toon. I haven't heard anything from people who play strictly alliance on if they get the repeating quest or not.

A few pets I would like to see: A hydra Lil Kraken red leg tarantula Lil Lich King with abilities like Necrotic Plague that jumps from enemy pet to enemy pet after its duration is through, army of the dead, remorseless winter, and summon valkyrs a little warlock with affliction and demonology attack...