As much as it would pain me (unless it was replaced with something equally good/rare), I could see FTGGOG being swapped out easily. It's by far the weakest point in the set from a casual fan perspective.
It's a crucial part of the set, while TETMD and Wicker Man (besides the backdrop) aren't.
That said, the only 3 songs that could excuse dropping of FTGGOG are Infinite Dreams, Brighter Than A Thousand Suns and Alexander The Great (but the last one won't happen). That said, Infinite Dreams doesn't fit into the thematics of the set and the second two would be moved into the War part, so the Cathedral set would last for only one song, Revelations, which is unlikely, since it's the greatest part of the stage set.
If I could tell them what to play, I would choose this:
I. War
1. Aces High
2. Where Eagles Dare
3. 2 Minutes To Midnight
4. The Clansman
5. The Trooper
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II. Religion
6. Revelations
7. For The Greater Good Of God
8. The Wicker Man
9. Sign Of The Cross
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III. Crime and Punishment
10. Flight Of Icarus
11. Hallowed Be Thy Name
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IV. Hell
12. The Number Of The Beast
13. Iron Maiden
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Encore:
14. The Clairvoyant (Bruce with a crystal ball)
15. Stranger In A Strange Land (Bruce in a polar explorer suit, trapped body in a see through ice)
16. Run To The Hills (Bruce on a stick horse)
What I expect? Clairvoyant replacing TETMD. That's it.