I noticed the writing has a recurring element. Some characters start as interesting, then the writing overuses only an aspect of the character ,making it eventually boring.
For example,I thought Aslaug started off as a very interesting character,she was smart and somewhat of a charming naïve princess.Eventually, the show started showing only the bad side of her, first a drunk, then a cheater,and then they made her a cause of killing Bjorn's daughter, no other side of her for redeeming the character.Same thing is now happening to Ivar,in season 4b he had many character sides that made viewers conflicted about him, should we feel bad for him or hate him,but now he's just the "evil" guy,every scene is just to show us how bad he can get,we get it already.