This is a bit out of the scope of the current discussion but I have to say that one of my hopes for the next Maiden album is that they completely remove all limiters on what Maiden "should be" -- use 7 string guitars on a couple songs, tune down below drop D, experiment more! Less clean intro/outros and repeating choruses. Look not only at Bruce's solo material or Primal Rock Rebellion but also at Maiden stuff which has used DADGAD, drop D, D standard. I'm not saying a whole album of down tuned or 7 string stuff but maybe sprinkle it in here and there. Bruce has stuff way down in A on Chemical Wedding (when played live, Roy Z and Adrian Smith used drop D guitars with an octave down effect on King In Crimson & Trumpets of Jericho -- Roy Z confirmed this in a tweet).
If this might be their last one, I want the gloves off. Relinquish a bit of control, Steve!