There's been an uptick of writing experts popping up online recently.
As someone who's actually a writer (I've got experience and official credentials), I think the only problem this season has is that it's a bit rushed. I think the show-runners should have done 10 episodes each for Seasons 7 and 8 to give the storylines and character development a chance to breathe and build. I have actually very little problems with the story itself. It's fine.
The only problem? No. The root of all the problems? Yes.
The heart and soul of a well-structured story is cause and effect. Something happens which causes something else to happen. Something else happens because of what happened earlier. Coincidence, luck, and randomness should be rare, and generally reserved for complicating an already established conflict or scenario. Sometimes, a single cause causes multiple effects (such as Ned's death propelling each of the other Starks into their respective storylines); and at its best, a story is typically able to juggle the interactions of multiple causes and multiple effects, which GoT has done admirably in its earlier seasons.
The problem with this season of GoT is that the show as been given so little time to breathe - as you have pointed out - that not only is the pacing of the story and the passage of time out of whack, but also the basic cause-and-effect dynamics of most of the previous seasons has been thrown out the window. In its place are deux ex machina moments that are instead meant to shock and awe and feel epic and exciting at face value, but upon closer inspection follow no rhyme or reason. The show openly contradicts its own internal logic and setups, first from an episode-to-episode basis, now on a scene-to-scene basis. We've gone from tightly-paced political intrigue to something that occasionally doesn't even function on a basic cause-effect level.
I have very few problems with the broad strokes in the story. I have very few complaints about what actually happens. But the devil is in the details. When you go past the broad strokes and examine how and why those things happen, then there's where the problems appear.
But hey... maybe I'm just talking out of my ass. I'm neither a writer nor do I have official credentials... so what do I know, right?