With the whole song-retirement discussion, I tend to take the middle ground and to be fair, Maiden did that with TBOS set too, at least to some extent; there's also a big bunch of fans who're attending a Maiden gig for the first time, or just love hearing classics time after another. That's fine. But instead of playing every single one or 3/4 from the Trooper-RTTH-TNOTB-2MTM bunch, it'd be appreciated if it was like "only" two and then something equally golden, but a bit less obvious - as they pretty much did with Powerslave, COTD and WY during TBOS tour. Then again, all of the mentioned work very well in LOTB set and at least there wasn't Wrathchild or Sanctuary stealing a spot from something a bit more "substantial." Wrathchild works very well live and I have nothing against it as a song, but for a 15 to 16 song set it seems a tad bit cheap, even when it balances things out well. But since pretty much everything from the "golden bunch" gets played during history tours, it's indeed appropriate to give them some rest during album tours. I've repeated this thing to death, but yes, I think that TBOS set did a lot of things right, where as TFF 2011 and Maiden England could have given rest for 2 Minutes to Midnight, for example, which would have also made the return of it this year much more appreciated.
Anyway, since Sanctuary and Running Free are indeed semi-retired already and one or two songs from the biggest hits is often skipped during album tours anyway, I guess FOTD might deserve a rest next time. Skipping FOTD in TBOS tour in favour of Brave New World wouldn't have hurt, but after being played on both history tours after Early Days one, it's not really realistic to even think about that. FOTD has been great this year, so why not to give it a rest for next (album?) tour? It's hard to top the current rendition anyway.
So, to answer the poll question, maybe FOTD and/or Wrathchild?
Since LOTB has given us such a brilliant renditions of even some of the most worn-out classics, it'd be cool if the next album tour followed TBOS layout and gave one or two of those songs a rest. A very healthy bunch of new stuff, two or three of the biggest hit singles, maybe TNOTB and The Trooper, keep Icarus, return Wasted Years and throw in something from the category of Die With Your Boots On, Can I Play With Madness, 22 Acacia Avenue, Man on the Edge, The Clairvoyant, Remember Tomorrow, Afraid to Shoot Strangers, Phantom of the Opera etc. to play the same role Powerslave and Children of the Damned did in 2016-17.

And then, maybe some "modern classic", meaning The Clansman, Blood Brothers, Brave New World, Dance of Death or maybe even The Reincarnation of Benjamin Breeg. Good sturcture with enough fresh edge to make it at least equally interesting as TBOS set was, while still retaining a healthy bunch of hits and favourites.