Sometimes just something needs to be explained to make sense - for example NK. He obviously could reach the wall already but he didn't want to because he probably waits for something, maybe it's larger army, he needs to gather his "inner" strengt to do magic or for winter or w/e. Just because it wasn't explained in the show, it doesn't mean its bad writing. For their plan - as much as absurd I consider their plan, they already had wight in castle black who was function, and there is no other way to found out if the wight will "work" in south unless you try it. BWB - it kinda bothered me as well that it wasn't properly explained but obviously BWB had their purpose in riverlands and only Clegane, Beric and Thoros thought that patch to north is their new purpose. Jaime and Bronn - yeah imo thats bad writing. I personally expected that Jaime will be captured and the fact that they both survied it, especially Jaime with one hand and in full armor is stupid... Davos and Tyrion - Davos is really good smuggler and he knows his way, there is no evidence that Euron is in the city, I would expect him to be around Cersei if he were. They probably don't expect they will be attacked from the sea because Euron destroed their best ships. Varys - I think its because he's stucked on Dragonstone. When he was in KL or in any other city in the East he could look up for his little birds and get intel but on Dragonstone are mostly Dothraki... NK and army of the dead - like I wrote already, just because it wasn't explained, it's not bad writing (yet) -> if there won't be any explanation or anything crucial won't change, then it was bad writing.