Genres aside, the biggest problem with over-amplified music is that one can't sing to it. I'm a trained opera singer, and I can't compete with amplified sound. When I can't hear myself sing, the music's too loud, and I stop singing because I know I will over-sing. And if I can't sing, I'm not worshipping. Then it becomes a concert. Nothing wrong with concerts, but they don't belong in a worship service.
I don't know that "can't hear myself sing" is necessarily a bad thing. For me, it's not the sounds that come out of my mouth, it's what comes out of my heart. And if I can't hear myself sing, then I'm not focused on myself, but the one I'm worshipping.