I'd much rather artists experiment with different vocal techniques in a single song like a guitarist might, rather than an artist screaming throughout an entire song or singing throughout an entire song.
I believe music is missing that experimental element and instead appealing to the masses, i'm sure many teenagers enjoy the screaming element of emo and new-metal because of the angst and anger released, however I think that vocals still have to be respected, otherwise it's just going to get real trashy. How loud and high can i scream "everybody should die" is what it'll get like.