(in fact, this is why I feel the majority of Maiden's early songs apart from frequently played 'classics' will never again appear - ie it would take Maiden months to remember how to play Alexander The Great, let alone practice it). Whilst there are complex songs on TTF, the band has recently written, practiced and recorded them and therefore the song structures should still be in the brain.
Secondly, apart from Nicko laughing in some interviews about how tough it is to play the 7/8 timing in Starblind and Isle of Avalon, those two songs do not seem overly complex to me. As a guitarist i have be jamming along to the riffs in Starblind and they are kind of typical Maiden riffs. THe toughest may be WTWWB...