I feel like before this is over, Unalaq will be revealed to be "controlled by Vaatu," so that Korra's Uncle isn't a horrible person and killed/imprisoned. To be fair towards that possibility, how would he even know about Vaatu? Plenty of people have gone into the Spirit World yet this is the first we ever heard of him, meanwhile Unalaq talked to him like they already had a plan and that it was all going bad.