I'm confused - I thought Davros was definitely coming back. I thought I'd seen pictures of his new look and everything! Perhaps I dreamt it?
Perhaps s-island means that the fearsome plastic-bag monster from Genesis is coming back to wrap itself around the Doctor's face again (with some assistance from the Doctor himself)? It would certainly shake things up a little bit.
I didn't watch tonight's episode because whats-her-face annoys me.