Actually I think Mike can be a whole band himself. He can rap, sing, play guitar, piano, and probably some more. He's incredibly talented.
On topic, I'd like to see him sing, but obviously I want him to rap and Chaz to sing, plus, if you go to an LP concert, you'll hear a lot of Mike singing, like on LIT, he doesn't just sing p5hng me a*wy, you can clearly hear his beautiful voice when he does backup vocals, and he also sings in Crawling and Faint when they do it live (not backup).
On the next album, I'd like to hear a song, or just a part or something, where Rob, Brad, Joe or Phi sing, not backup vocals, but lead. That would be cool, or it would be cool if they can sing, that is.