I'm talking:
Someone who is experimental with their sounds
Someone who pushes the genre to another level or creates a new one
Someone whose influence is easily spotted and appreciated.
For hip hop I'd say MF Doom. I feel like his style was hard to nail down becaus
e he was always trying new things, sampling things you didn't commonly see sampled in hip hop, and he's made it cool for rappers to have gimmicks beyond "gangsta, invincible MC or dope boy".
For R&B gotta give it to the weeknd. His first album doesn't sound anything like his latest album. He's also brought a type of grittyness and realness that you didn't get before in R&B all that often. He was singing about the real shytty parts of hollywood and fame.