I'd like to see flying, either via magic or via Icarus device. Why? Because we know the engine can handle it and animesque battles in the air but with medieval weapons would be awesome. On that note, I'd also like to see more reflexive combat physics, i.e. knockback and shock effects that affect more than corpses.
I'd also like to see more details to set it aside from the generic. Little things like, I don't know, trees that grow in latticed groves that become tubes/ordinary-seeming animals with odd traits or inherent magic/ weird atmospheric effects. It needs things that say "This is not earth in the anachronistic and magic middle ages".