I think I figured a couple of things out. White text for speculation/spoilers:
Aerys II did hear voices. He heard the Bloodraven. Aka Brynden Rivers. Rivers was an illegitimate Targaryen. As the greenseer, he knew of the white walker threat and wanted to warn Aerys, his relative, to save him and the rest of the kingdom.
Only he botched it, badly, much as Bran did with Hodor. It’s quite possible that he botched more than that, but regardless, he caused much pain and set all of these events in motion. All of the misery and upheaval we have been watching was because he was meddling with his greenseer powers.
So when Bran calls out to Ned, Brynden’s facial reaction is noticeable. He doesn’t want Bran to make the same mistakes he did - he is clearly not ready for it.
I suspect that Bran is going to do more harm as he discovers his powers. Starting with going back to the Tower of Joy (as soon as he is capable), now that Brynden isn’t there to stop him. That may even be the finale of this season. He may even end up playing a hand in what happens there, for the worse.
In his guilt, and to save the world, he is going to end up sacrificing himself, IMO. He’s destined to become a martyr, and while we may have a 3 headed dragon, Bran is going to be key to the end of the war - to fix what the Children did thousands of years ago.
Going even further, he may end up removing magic from the world, because it is simply too dangerous
Also, on a much lesser note, I finally figured out why the Umbers turned Osha and Rickon over to Ramsay. Its part of a plot by the Umbers to take Winterfell back. Osha was there to watch over Rickon and take a shot at Ramsay if she could (failed). But ultimately, the Umbers are gonna flip on Ramsay and install a Stark (Rickon?) as the Lord of Winterfell.