In defense of Piece Of Mind, it is one of Maiden's most overlooked album, atleast from the classic era. Mostly remembered for The Trooper (rightfully, a classic!) or probably Flight Of Icarus but I will say the instrumental parts are really underrated from the album where the band nailed it! Be it the mid section of Where Eagles Dare, Revelations (the song alone influenced the band In Flames finding their sound) and obviously To Tame A Land. These songs genuinely sound 'progressive' in the sense of dynamics and change of tempos, without noodling around just for the sake of making the songs lengthy.