The Future Past Tour sold out the UK leg in seconds.
Let's face the fact that Maiden are going to be a stadium act from now on, which makes a lot of sense under every aspect: more money, less shows that needs to be played, better stage designs (I think they'll upgrade for good next time), more coverage.
They will surely add arenas and festivals but they won't go back to playing arenas in most of the European countries. Whatever the theme of the tour is, because the demand is there and now that every show might be their last people are not missing the chance to see them.