R&B is changing, and Ty Dolla $ign is at the forefront of the movement.
20 years ago, R&B sounded a lot different than it does now. Unlike rap, which has a whole subset of artists devoted to reinterpreting, reliving and/or unimaginatively rehashing a perceived "golden era" of sounds, R&B singers generally don't seem too concerned with looking over their shoulders, save for the occasional homage to James Brown, Michael Jackson or R. Kelly.
Not only has the genre's sound progressed, as is almost inevitable, but so has the perception of its stars. Whereas there used to be a distinct, well-defined line between rappers and singers, that's now vanished in the wake of people like Drake, who started off singing his own hooks and now blurs the line between singing and melodic rapping, and Future, who rarely (if ever) turns off the auto-tune, but is almost always referred to as a rapper. Nowhere was this shift more evident than the cover of XXL's 2014 Freshman issue, which had two men more frequently referred to as singers-- August Alsina and Ty Dolla $ign-- standing alongside rappin-ass-rappers like Jon Connor and melody-friendly MCs like Rich Homie Quan alike.
More so than Alsina, who fits more in the classic R&B mold with his infrequent rapping, Dolla $ign is the single best poster boy for R&B's new wave. His music is no doubt cutting edge, but in addition to his sound, the way he's constructed his career is particularly revolutionary, which is why we think he represents the future of the genre.