The brightest talent from the Bay Area’s eminently twerkable, social-media-driven rap rebirth, IamSu!, has nimble rhymes, a killer fashion sense and a catalog of great mixtapes. But he doesn’t do enough to stand out on his first proper album. Outside of its strong singles (“Only That Real” and “What You ‘Bout”), Sincerely fades into rap’s existing trends instead of bucking them: “Intro” mirrors Drake’s or Kendrick Lamar’s purpler moments; the title track’s “‘G’ Thang” breaks and swooning strings sound more Dre and ‘Ye than Bay. This side of IamSu! might work wonders on the pop chart, but it won’t be blowing up on Vine.