Well i don't actually understand the complaints. I mean this is just how this manga is...
Yeah normally people (esp. people with influence) gets scared of eyes (or looks), gets stunned when talked back to right?!...
Akatsuki no Yona was never a masterpiece of world building and characters and the idea of good and evil. And it's fine since it's a shoujo or since this have been how the things were for the past 200 chapters......... But it's still very good with it's openings and all... So what's the deal exactly?
But about the plot armor, Hak has proved himself as a commander in the battle with sen province and as it happens they're about to go to war... Oh and Yona has gain respect of the adviser proving herself useful (also this chap serves for that as well btw) and still has the leverage of having 4 dragons... YES they could show how yona found out or how hak wasn't killed BUT, as a shoujo, this manga attracts people mostly by romance etc.. So as not to slow the story down (or lose audience) they have to leave somethings behind...