I may as well tell of my main gripe with some early Maiden. Repetition. Especially the chorus's. Just repeating the song title. Grrr!
Running Free is awful. I know they aren't exactly early but
Heaven Can Wait and
Fear of the Dark are two more culprits.
They don't tend to fall into that trap anymore.
Probably because they've forgotten what a chorus is recently.
I ****in' love Maiden by the way. It's that love that allows me to be critical.