4. Jon Snow's True Parentage
Jon and Arya are revealed to be two of GRRMs five major characters - the others being Daenerys, Bran, and Tyrion. Considering they are protagonists, and essentially on the gallant side of the heroic spectrum - as opposed to the villainous - its perhaps not surprising GRRM transferred the theme of incest from House Stark to House Lannister. GRRM is not averse to turning traditional fantasy tropes on their head or breaking the High Fantasy mould entirely, but establishing what was seemingly an incestuous love between pivotal characters may have been a touch too much, even for him. The most revealing item in this early draft though is what effectively amounts to confirmation of a pre-existing theory (see here) about Jon Snows parentage. In the context of outlining the love triangle between Jon, Arya and Tyrion, GRRM confirms that the truth about Jons parents will be uncovered: their passion will continue to torment Jon and Arya, until the secret of Jons true parentage is revealed in the last book. This goes a long way to confirming the belief of astute fans who pieced together GRRMs clues that Jons parents are actually Rhaeger Targaryen and Lyanna Stark.