I've often felt that "Killers" would have benefitted a lot had Murders In The Rue Morgue immediately followed The Ides Of March. Murders... would have been a far more effective opener than Wrathchild. The Ides Of March/Murders In The Rue Morgue should have been the combo that opened the album.
As for Die With Your Boots On, that's actually my fave song from Piece Of Mind, I love the tension and the build of the fun but macabre pre-chorus, and the solos and harmony section is one my fave sections of any Maiden song. H's solo in Boots... is one of his finest solos in my opinion.