"Check On It" is low key her best song It's so perfect. That's what's been wrong with her music since 4 and why she can't get hits, that sense of FUN that used to define her music before is gone.
Rihanna has never changed music. She changes with music though
Ehh I'd argue "Umbrella" re-popularized monosyllabic hooks, which defined pop music until the end of the dance craze. "Po po po poker face" wouldn't have happened without "Ella ella eh eh eh".