I just caught up on all of the second half of season 4. Thought it was as good as the show has ever been. Marsters and ASH were both brilliant as usual. Though I would have liked to have seen more of them on screen together.
It's a bummer that the last season will only be six episodes. Seems like a sort of random someone just pulled from a hat.
I suppose Paracelsus will be settled-up in the first episode, with Claud's sister introduced as the big bad for the last few episodes. I guess the only thing to do in the meantime is speculate who they'll cast.
I suppose the obvious choice would be Allison Mack. Aside from being Scagliotti's predecessor in the great lineage of Ali-techno wizards, they do look a lot a like, and Mack meets all the criteria for being a WH13 guest star.