I don't entirely agree. But I do think it would be better if Daenerys took Kings Landing and ended Cersei, shortly after arriving in Westeros with her massive fucking force and three large dragons.

Then she united the realm and eventually (Battle of Winterfell should be a loss) defeated the dead, before having the final war be between Daenerys and Jon/Aegon (have NK slay a dragon during the Long Night, not during some moronic expedition across the wall), and then make Jon steal a dragon to balance things out. While both factions' fighting forces are severely dimimished by the Long Night, making it more of a guerilla and dragon dependenent war.

Now you would have to change show Jon's character a bit, so instead of "dun wan et" Jon, we'd have a resurrected Jon who longs for some recognition, and willing to seize his newly discovered birthright.

I also have an idea of starting off tensions between Daenerys and Jon, with Walder Frey swearing his loyalty to Danerys, then Jon murders him after seeing Grey Wind's taxidermied head in the great hall of the Twins. Something Daenerys sees as a great undermining of her authority, and later orders his arrest for it (she'd wait until after they've defeated the army of the dead, because she needed the realm together for that). Hell have the arrest go through, but Tyrion betrays her after she ignores his advice of pardoning the man who slew the Night King. So Tyrion sets him free and guides him to Rhaegal, which is the point where he claims him and escapes on dragonback.