The idea that Jon would make a good ruler is also bizarre at this point; he's shown himself to be emotionally gullible and open to manipulation. If he was king someone would definitely come along and start whispering in his ear and get him all confused in no time!
Only person left in the show who would make a genuinely good monarch is Sansa
. She cares enough about doing broadly the right thing to be a fair ruler, but she's also hardened and clear in her vision of what's actually going on.
Although, presumably there IS no Iron Throne now and Dany intends to rule from Dragonstone?