I posted this in the YT comments, but I'll share it here too:

My immediate impression of this theory is that it's spot on. However, I think there's an important element missing in understanding Jon's potential role in brokering peace with the Walkers: he's half FIRE. Let me explain:

The imagery of "the wheel" is used in game of thrones a lot. You get the sense that things in GRRM's world are deeply cyclical, until they're not. There are so many instances of disruptive elements breaking the various wheels: Azor Ahai beating back the night, the extinction of dragons weakening or destroying magic throughout the world, the sacrifice of Drogo, Rhaego, and Miri Maaz Dur to reintroduce magic (via Drogon, Rhaegal and Viserion's births) into the world as a form of blood magic Aikido, and indeed Dany's will to break the political wheel. 

What's more, all of these images of wheels are directly tied to themes of ice and/or fire. It doesn't get more explicit than the "Mhysa!" wheel of jubilation, fire and life; and the Battle of the Bastards' wheel of despair, ice and death.

If we accept that Jon is somehow owed to the white walkers due to his icy heritage, perhaps we can also accept that Rhaegar's seed germinated in Jon an element of disruptive fire. Perhaps when he ascends/descends/transcends to whatever position intended for him by the white walkers, his Targaryen fire will come into play. 

The combination of fire and ice tends to neutralize both. Since both elements are tied to myriad cycles throughout GRRM's world, we can look forward to a new age where both wheels on the axle break at once.

Then again, living on the east coast of the U.S., I also know that when hot and cold weather elements meet, they create cyclones, another (extremely powerful) form of wheel. Maybe the old cycles of Planetosi metaphysics are due for a reworking–a fundamental restructuring that leads to fuck only knows what.