This is an excellent post.
My feeling is that the ShowJon's character development basically stopped after his resurrection, and, indeed, started regressing.He actually seems more naive, vulnerable and less experienced than he did back in series one. He also seems to have forgotten all the lessons he learnt about leadership during his tenure as Lord Commander, including the very reason why he got killed in the first place.
it is quite obviously a writing problem. ShowJon is now just some emo kid who walks around looking wan, confused and troubled. He's completely unbelievable as King in the North; he has no gravitas at all anymore. And when he was proclaimed King, there should have been talk about who he would marry to build an alliance (this would have been a perfect opportunity for Sansa to show her painfully-acquired diplomatic skills, and would have been a source of tension between her and Jon in light of the possibility of his death at both Danys' and the White Walkers' hands). Marriage alliances were one of the major themes in the earlier series, and the reason for the downfall of Robb Stark at the hands of Walder Frey; this stuff is important in Westeros.
For example, instead of requesting Dany's "help" in mining the dragonglass; why didn't he approach her with a marriage proposal? It's not like this would be unusual in Westeros, nor something Dany would not expect. She's done it before. Then we could have had a very interesting dynamic set up whereby the idea of an arranged dynastic marriage between the North and Dany creates fallout with other Westerosi houses and other singular supporters such as Tyrion (who may or may not see trouble ahead in such a match), and that would have made the revelation about Jon's parentage even more shocking, particularly if it came to light after the marriage had gone ahead or if it was used as a reason why the marriage could not go ahead.
It would have also provided a viable reason for Dany and Jon to cross the wall with a couple of dragons. If the proposal is that Dany marries Jon in order to secure the support of the North for her claim to the IT in return for dragonglass and help with the WW, then there would have been a reason for Jon to insist she goes to see the WW threat to the realm herself, and that's when she loses Viserion to the NK.
I also think that Jon losing his side kick/foil in Sam when he went to Old Town has caused story problems. For the last few episodes, Jon has had no other appropriate character by which an exchange of dialogue can take place that reveals how his internal thinking about the situation with Dany, his position as King in the North or the idea behind the wight-show. All we see are his decisions with no insight into any of his reactions to prior actions that then provoked said decisions ~ and he's supposed to be a primary protagonist. We are supposed to know why he is doing things and making the decisions he is ... but we just don't. I can't particularly figure out just why he's in love with Dany or why she is in love with him. He hardly knows her, compared to someone like Jorah whose feelings make far more sense.
In short, no-one is really confiding in other characters anymore, so there's no revealing insights. Everyone has become a lone island in the story.