What killed the solo? Too many bands with shallow songwriting, combined with too many guitarists who thought they were the next EVH, and played too many notes, showing off the latest technique, until you couldn't tell one band from another. If you want to revive the solo, write good songs, and make you solo part of the song, not the other way around, every solo shouldn't be an excuse to play as fast as you can, a chainsaw is fine for cutting wood but people really don't want to hear a chainsaw everytime the guitarist takes a solo.