Atavism does lack something of the epic/classic feel of the first four albums. Seems like a decision to ... i don't wanna say 'streamline', but focus the songwriting in a different way than existed on the earlier albums. It's still a very good album, but I don't think it has the everlasting (to me) appeal that the other four, especially Twilight and Traveller, have.
For a while I was listening to Atavism a couple of times a day, maybe I'm just a bit burnt out on it for now, but I hope longer, more epic and fantastically themed songs make it onto the 6th album.