That's what my colleagues and me also talked about. To me it seems the writers realized "Hey.. we have this character here that hasn't had a sendoff and we are approaching the end of the show. What do we do?"
This is the only reason they had Jon artificially be left behind so they could close the book on the Benjen "storyline" and i agree it was lazy writing, much the same other points (my pet peeve are the 3 huge metal chains they use to pull put the dragon from the lake.. where did these come from?).
The show did take liberties from the books and had to given the limited run time.. whenever an expansive book series gets adapated for the screen there are things that will end up on the cutting floor (Lord of the Rings Tom Bombadil for example) but the show seems to have become careless and careful viewers notice these things (even i start to notice and that's telling

).
I don't know how close Martin is involved anymore with the writing ( i know that in the early season there was at least one episode where he wrote the script for) or how much detail the producers got from Martin about the unreleased books but it seems that either reality and the pressures of producing such a complicated show with even less episodes as before or just plain shortcutting their way and improvising scenes to get the general story moving.
I don't know if it's my own prejudice but GoT got a lot more predictable and Hollywood heroic since they didn't have books to fall back on. No major character has died in a long time and they get themselves into big trouble but get rescued in true Hollywood style (Battle of the Bastards for example). No more Red Weddings, Khal's dying from infected wounds or Ned Stark style beheadings that put GoT on the map so to speak.
I am regularly watching reaction videos and nearly all are reacting or saying the same things nowadays.. when the Lannister convoy was attacked everybody expected Dany to appear and she did, when the guys were about to be overrun by Wights everyone called for and expected Dany to save them and she did. Everyone knew Jon would be resurrected (they practically telegraphed it when Melisandre arrived at Castle Black and the year in between it was the worst kept secret of the show).
Don't think i don't enjoy the show.. it is still in my top 3, depending on the episode the top show, for me and i enjoy when the good guys get a break and pull off a win, Lord knows they couldn't for a long time on the show but the compression and change to the show format does show a bit.
The final season of course may change all that.. in GoT there is no win without a cost to be paid either immediately or later so i fully expect several characters to die, even amongst the top cast so in the end it may even out and give us this bittersweet ending that's been teased for years.