I think when 7th Son came out I, along with my Maiden loving mates, was still reeling from the synths on Somewhere in Time. We hoped they'd ditch them on 7th Son and they just seemed to add even more. At the time it was as you say a real love/hate thing, for both those albums. Now I love them both and rate them right up there. I also really like No Prayer, and see it as probably Maiden's most underrated album. It was Fear of the Dark where I started to struggle, and continued to until Brave New World. That said, the song Fear of The Dark is a real highlight live.
Regards Maiden England, it's a superb film of a great set, from a time when Maiden were on fire. Probably not quite got the energy of Live After Death, but the delivery is spot on and the setlist unbeatable. The 7th Son tour was excellent, and seeing the band play Killers (somewhat unexpectedly) remains one of the real highlights of my gig going days.
We had a similar situation down here. I bought 'Somewhere In Time' on the day it was released, and disliked it instantly, couldn't believe my favorite band were using synths.Because of my dislike for it, i was apprehensive about the follow up.
It's funny, these days, whenever i spin 'Somewhere In Time', i'm reminded that it's a superb piece of work, and the ignorance of my youth.