I was venting on FB about the whole finale, back when it happened, and a friend noted that having and omniscient and heartless king seemed like a horrible idea. Then I came across this twitter post that really gave the idea some weight:
https://twitter.com/vornietom/status...22571210838016
tl;dr
The 3-eyed Raven is an evil multidimensional being who is using Bran to rule the world of men forever, in the guise of a helpless cripple who *accidentally* let all the people who would stop him die or be sent away.
It's too bad this pretty good fan theory is more thought out than the sloppy rushed season we got