Ivar is such a wasted character, they could have made him empathetic and had him be the "underdog" story for the show, someone you could root for to take over where the space after Ragnar left. That's what it seemed like they were going to do when Ragnar took him to England and everything, and then this season pretty much cemented him as a crazy lunatic villain that you definitely do not want to root for.
Like with Ragnar, what made him such a great character was that even though he did some bad things, he still did some good things and he grew as a character, he had an open mind and learned and wanted a better thing for his people, he didn't just want to "pillage" and war, on top of all of that he was smart as heck too. This is something that the writers seem not to grasp when they were writing for Ivar, because they had part of this sprinkled into his storyline on that season when he was with Ragnar, and then they all but just dropped that.
Floki's story continues to be a giant waste of time, like it's not even connected to ANY other storyline or main characters, in ANY other show his character/story would have ended when he went to sail away and that would have made space to focus more on the rest, but instead for some strange ass reason they decided to just keep following Floki and telling his story which, unless they bring him back into the fold somehow, makes no sense at all.
where are bjorn's kids
how is ivar still the boss
Bjorn basically abandoned Siggy. Aslaug was supposed to take care of her but she didn't and then Sigurd found her drowned in the river. After he told Aslaug and Ivar what happened Ivar laughed and Aslaug didn't give a shit either.
After this the writers decided to basically ignore it and Bjorn didn't even care or mention it anymore.