I think that to do a LAD themed tour it's enough to celebrate 50 years. They could also do a special reissue as they did with Number of the Beast/Beast over Hammersmith.
The main reasons I'm starting to think they will do something like that are:
- Bruce said various times that he wanted to do songs like Rime again
- There are quite a few stadiums already booked for next year, and LAD represent their most popular era. Just advertising the tour as a celebration of that era will be enough to sell shitload of tickets.
- It will be 40 years since its release.
- The LAD setlist is basically a greatest hits setlist. Also, in 2008 they didn't play songs from the Hammersmith shows (22 Acacia Avenue, Wrathchild, Phantom of The Opera). If they include those then it can be seen as a 50 years celebration too.
- The tombstone which gets uncovered on the screen(s) during Hell on Earth it's the same as the one on LAD cover. We know Maiden plans way in advance, and that's the kind of hint Maiden give us.
- The setlist wouldn't be too demanding, at least from the "we gotta learn these songs again" side. Aces High, Children of the Damned, Powerslave... all songs they've been playing "recently".
Again, it's just and idea that popped in to my mind.