My previous theory:
seems much less likely now after the last episode of the season.
Much of the above remains true, but with two critical changes.
Dany's fleet included Targaryen, Greyjoy, Tully, and Dornish flags. Tyrion is not the one to inherit the South, Dany is.
Sansa has stepped aside to allow Jon to rule. Jon is now "King In The North". Sansa is not the one to inherit the North, Jon is.
As such I think the TV show will end with the bit "expected" Jon and Dany on the throne. Sansa is being set up to rule the North while Jon is down south. Tyrion is being set up to be Hand of the Queen. So on and so forth.
Also, I think the book WILL end with Tyrion and Sansa on the throne, Jon and Dany dying in the final battle. I think that this is Martin's idea.