Heavy metal subgenres are constantly evolving and I proclaim that the next big thing will be nü-djent, a sort of combo of nu-metal in the vein of Linkin Park and djent like Periphery and Animals As Leaders were doing.
There are already bands that are arising that are melding rap metal and chuggy riffs. Last week, Metalsucks alerted me to Devastator, a band with hip hop lyrics and djenty riffs:
Of course, Britian's Hacktivist have been rap-metaling for a while now, even releasing a pretty great cover of Jay Z and Kanye West's "N***as in Paris"
The only thing the genre needs now is a breakout band with a super catchy song. I feel the elements of djent are melodic enough for a wider audience, even some radio play. All it will take is the right band to capture the right combo of djenty and nu-metal riffs and this will be the next big thing.