When Wiz Khalifa arrives at the Rolling Stone offices the day before the release of Kush + Orange Juice 2, the sequel to his cult classic 2010 mixtape, he wastes no time getting right into the music.

Wiz’s deep cuts are filled with cinematic instrumentals, emotionally raw verses and a laid-back honesty that shaped the tone for an entire generation of rappers. These songs weren’t always made for ...