Well it is impossible for Maiden to go on something like Metallica with setlist changes. Firstly, it is much easier to do it with a 4 piece than 6 piece band.
And Maiden band members are travelling separetly to shows, most probably they dont hang out too much together and with change of setlis as far I saw in Metallica vlogs, guys before every show play those new songs in a small rehearsal room at the venue.
There was one video about Metallica on tour where they show the day of the show. Guys are coming much earlier at the venue, rehearsal rotation song, then they are deciding what are they going to play. They are taking stats of the city where they play and try to dig some deep cuts for the cities where they often playing.
Their managment and marketing team is on next level than any other band, and band members are really hard working guys for making so much effort about setlist.
I am aware that Maiden cannot do that, but at least they can do some special shows. Like perfect scenario, after LOTB tour in December they could play 1 or 2 nights at Hammersmith with PPV live stream online. Playing full NOTB and other deep cuts. But ok, we have a new beer now, that is more than enough.