Personally I think that the problem is each episode has no clarity of vision because we bounce from place to place learning pretty much nothing new.
Tyrion's trail by combat should have been one stand alone episode and it should have been the latest one. That way you can save the reveal of the mount to that latest possible moment and make Oberyn a surprise. Instead every things been mapped out all of the interesting surprises available to us have been wasted on sloppy writing on the part of the script team.
They are too busy trying to do a crazy kind of lock n load meets rashomon with dragons thing instead of delivering tight, super fun episodes. Each one of these things could have been a roller-coaster instead it's like watching one of those stupid monitors on the fancy bikes in the gym that run a really crappy video of where you are riding.
I actually agree with this. If you keep reading the books, you will be surprised how some chapters contain like 4 episodes worth of plot for a single character. The books dance all over the place, but the chapters have great pacing, often end on hilarious twists, and there is an absolute shit ton of expanded characters and events that makes everything feel like a living, connected world.
This show is at its best when it takes its time in a setting, letting a mood and environment really sink in and getting the actor's to do some real work. Episode 9 of this season is supposed to be mostly (completely?) contained to one setting, like Battle of Blackwater Bay in episode 9 season 2, so maybe that will deliver.
In fact, in Storm of Swords, one of Tyrion's chapters begins with the last day of the trial, when Shae testifies, and you remain in his POV until the conclusion of his trial by combat. It is also one of the best and memorable chapters in the books.
Also you are describing "foreshadowing" which is a staple of storytelling. Its just the show, much like all popular TV shows, usually does it in a hamfisted way filled with exposition, to remind casual viewers who the characters and their motivations are.
If you remotely enjoy the idea behind this show, read the books, they are terrific.