You can't talk about a "dramatic power vacuum" without presenting Ivar as a contender. He will literally be filling that vacuum in the fiction ("fact"ion since it's historically based?), but I would put forth Alex Andersen as a new dramatic focus. He has been crushing it.

Okay, I thought I was reading into too literally, but I suppose the Bjorn/Bear thing is there to throw us off the scent.

Maybe he's been changing back-and-forth into Rollo's shirt? That would explain why it's missing half the time.