You may be on to something. The whole thing could have wrapped up at the end of the red wedding with Dany invading and taking over a broken kingdom, and then Lysa Arryn could have released she was behind it all with Little finger to the world and everyone would have realized it was all a big misunderstanding. That was probably as far as GRRM planned out initially. It also explains why thr White Walkers seemed to slow down after the fist of the first men.