Quoted from PinballCharlie:
I gotta figure this out then since we likely have the same TV. I switched from streaming thru the TV interface to my Apple TV after the first 40 minutes, and it seemed to clean-up a bit, but the show wasn't as dark at that point. I tried HDR Medium earlier, but no better. I think I need to revisit the episode and watch the first 45 mins through the Apple TV.
I was irritated for at least half of the episode last night. Not because of the action, but because I couldn't see it well. I readjusted my TV 3 times during the episode, and just couldn't get it clear and looking good. I've never had so many problems with the dark scenes of GOT. It was just too much action that was being obscured by the "other things" going on caused by (no spoilers here). I felt that because of this, the battle for Hardhome was a lot better. This should have been more epic, but unfortunately the show runners forgot that we use TVs to view the show.
In the end, I liked it. But I was pretty irritated that I couldn't see it well.