Actually Wrathion and Kairozdormu (a bronze dragon from the last patch) did this, using a bronze drgaonflight artifact and enslaving Garrosh to gain the trust of the old horde and stop them from drinking the demon's blood.
Wrathion wants to strengthen Azeroth because he had a vision of the demons bringing the apocalypse, but whether he lost faith in the Alliance/Horde or just want to prepare them is unclear.
Kairoz rather wanted to use multiple versions of old horde to become the next power mongrel, but Garrosh decided otherwise and killed him to take matters as he saw fit and reunite with daddy andcorrect the mistake that tainted the Orcs honor and stuff.
He then taught them how to use technology to be stronger instead of the demon blood, and used what remained of the artifact to connect Draenor to our Azeroth hoping to do what the original Horde couldn't do and conquer it.