Actually, the reasons you mentioned were exactly the reason I *DID* love AMOLAD. I didn't hit a song that repeated the same phrase eight times until 3/4ths of the way through the album. It was incredibly refreshing. And yes, there was some of the "formula" there, but it wasn't as in your face as the rest of the reunion albums. I still think it stands out among all of them.
The Final Frontier is the same way. Yes, there's the final frontier, the final frontier, the final frontier, the final frontier, but then that's it with the endlessly repeated lines for the whole album.
Iron Maiden has basically spent at least the past two decades of studio albums perfecting the transition of their style of music into a full-on prog metal context. They naturally evolved into a proto-prog style in 1988 for
Seventh Son of a Seventh Son, but I think that scared Harris at the time which resulted in that little diversion into
No Prayer for the Dying which continued over into much of
Fear of the Dark.
The X Factor is the first album of what I would call the modern era of Iron Maiden, and it's really been a progression from there with 'Arry and the guys becoming more ambitious and trying to figure out how to be a prog metal act while still being Iron Maiden.
Virtual XI is evidence of some of the hiccups that came with that transition (though I still think it's a solid album), and, yes, to some extent
Brave New World had similar problems, though these were lessened by the addition of Bruce and H and the high quality of songwriting across the board, despite the repetition.
Dance of Death is just overall not as good as BNW from a songwriting perspective, though there definitely are gems. But on these last two albums I think they've really come into their own in their current style, which is still easily recognizable as Maiden but much more ambitious and proggy than, say
Piece of Mind. I'd definitely rate AMOLAD and TFF as among the best albums of their discography, with TFF maybe being my favorite Maiden album (I think TFF has slightly better songwriting than AMOLAD—The Longest Day meanders a bit and I'm not a huge Out of the Shadows fan).
That's why I'm really excited for this new album. It seems like yet another attempt by this band to be more ambitious as musicians and to continue to tweak and perfect their little 20 year foray into prog. The presence of three 10-minute-plus songs and a smattering of shorter tracks as well is quite exciting, to me. What other band would write a song equally as long as the longest song of their career AND one five minutes longer than that for their 16th studio album? I'm not nearly as big of a Maiden fan as I once was, and I rarely listen to them anymore, but I am definitely anticipating the release of this record.