I'd like to see a return of ALL the various enemies as long as they're lore appropriate for skyrim.
Really though, I've always wanted the water to be more frightening. Sea monsters, lake hydras, tentacled things that you never quite see the entirety of. Crossing any water unless it's a pond should be a frightening aspect. Especially with how cold Skyrim may be.
it should, all oblivion had was slaughter fish, morrowind did a better gob with that at least they had the dreughs, those things were scarey man haha,