First of all, 80's metal was melodic. There weren't many progressive bands back then, and when people think of the term "80's Metal"; they're thinking of melodic metal.
Second, a hook. 80's Metal had hooks and bands today trying for that style all know that a hook is essential. The bands where a lead singer sang a chorus solo, with no BGV's, were few and far between. Meanwhile, bands with BGV's, such as Motley Crue, Def Leppard, Skid Row, Bon Jovi, and even Guns & Roses ruled the scene with great hooks.
Lastly, Brad, you're right on...the lead guitar solo and preferably, solo fills. When I consider a Christian example of 80's Metal - Whitecross - their music was full of solos from Rex, but also solo fills. The best example of this ever, Christian or secular, would be Dokken's Back For The Attack.
To me, its all about the music. I couldn't care less for the attitude, lifestyle, etc. That's all meaningless. 80's Metal is defined by being melodic, having hooks (the bigger the better) and lead guitar solos (the more the better).