I don’t understand the reasoning here, are you saying that GoT was a tech demo? To me it made sense that as the show got further along and the situation grew more dire that it would be visibly darker as a metaphor.
The Craster's fight and the wall fight were both at night and looked great. But maybe they should have been a bit brighter so there was more room for the narrative dimming and actually seeing things. This all feels like betting into an empty pot, though, because the darkness of episode 3 isn't even a top-10 season 8 complaint for me.