I dunno about more progressive. I think the next album is probably going to be a mashup. There was a lot of discussion during the last album of looking at shorter, more rock-like songs. But I don't think the Traditional Harris Epic is going to get any shorter, either. It's definitely been swinging up the last three albums.
What I think is we're going to see more Janick on this album. The Final Frontier was very Smith, not so much Janick. Of course, the addition of His High Lord Adrian Smith to all songs is irrelevant, for we all know that Adrian Smith wrote all Iron Maiden songs and secretly played the drums on Virtual Eleven, but it certainly has a different feel than a Gers-heavy album.