Given how at the end of Dance Jon is still at the wall and is dead/dying, Dany is in the middle of bumf**k essos somewhere and previously had no plans to journey to westeros anytime soon and the lannisters are still in power in on the iron throne and war has come to westeros again the Euron and Faegon causing trouble. With all of this going is it will it be possible to bring the story to an end in just 2 books? even if both Winds and Dream are large volumes like Storm and Dance being 1000 pages
Two more books should be enough, if the two upcoming books are gonna be with the same pace and focus like ASoS.
But it won't matter actually wheather he needs two, three or fourtyfive hypothetical books, because..well I don't really have to say it, do I?