I actually like this ending I've seen on Reddit:
"To me, this foreshadows an eventual Jon death and Daenerys on the throne, but wishing she could have back what she lost, pregnant with Jon's child.
The past few seasons, especially the last episode, have built Jon to be too good to sit the throne. He's morally just, trustworthy, honorable, he's basically done nothing wrong, he's willing to give his life to save the Kingdom and its people.
Daenerys is still flawed. She's still learning. Despite her lessons in Essos, she's unaccustomed to Westeros. She's making mistakes, breaking hearts, doing what she thinks she needs to be doing .. she reminds me a lot of Stannis, who eventually learned he had to save the realm to rule it.
I truly believe Jon will die to save Westeros, and Dany finally becomes the leader she has to be, but she rejects and maybe even hates the throne because it cost her everything: Jon, dragons, the Unsullied, the Dothraki, possibly more than that, leaving her only with Jon's child. She will sit the throne and realize it's a hunk of twisted and burned metal, not her red door, not her home, not anything. She has yearned for it and it's nothing she wanted.
This fulfills the bittersweet ending: Jon is dead, having given his life for Westeros, and Dany gets everything she wanted--only to realize she hates it and lost everything."