The answer is actually quite simple: Steve Harris. While the three main songwriters of the band have almost always been Bruce, Adrian and Steve, Steve has always been the band's head honcho. And upon investigation, it's clear that over the years, Steve has become more and more bent on the material being done his way. A lot of the material nowadays is apparently mostly written by Adrian and Bruce, but Steve always has to throw in something to the songs too, whether or not it's actually necessary. And overall, Steve appears to be stuck in the mindset that every new Maiden song is an epic off of Seventh Son, as Adrian and Bruce have both shown they're more than capable of writing what could be interpreted as an evolved and modernized form of Iron Maiden. Not to mention Steve's requirement to have Kevin Shirley produce all of the new albums, and Shirley is a rather poor quality producer IMO. Bruce's solo albums were produced by his guitarist, Roy Z, and a lot of folks would much rather he produce the Maiden albums.
Oh I know that. :) And while it pains me to say it, as Iron Maiden was the band that really sealed the deal for me and metal, I'm inclined to agree with you. They're more or less to metal what AC/DC is to hard rock. I'm actually pretty close to saying that Bruce's AoB and TCW solo albums are the two best Iron Maiden albums that Maiden never made.
http://www.youtube.com/watch?v=sgTT90gFndM
Oh I know that. :) And while it pains me to say it, as Iron Maiden was the band that really sealed the deal for me and metal, I'm inclined to agree with you. They're more or less to metal what AC/DC is to hard rock. I'm actually pretty close to saying that Bruce's AoB and TCW solo albums are the two best Iron Maiden albums that Maiden never made.
http://www.youtube.com/watch?v=sgTT90gFndM