I was watching an old View interview the other day (2000, maybe?) where they were asked why Joey and Lance didn't get any solos. They didn't really answer it (Lance looked like he wanted to crawl into a hole), but Justin did say that without the bass and Joey's baritone, there wasn't a full sound and that their harmonies wouldn't be what they were without them. And I agree. His bass voiced definitely played a role in completing the sound.