Yes, Slave 4 you was risky, I remember when I was wating a pop bop ala Oops and Baby, and then Slave happened, Me against The Music was risky, Gimme More was risky, but more than risky I see an evolution in her music to makes a perfec pop sound its not like Christina, her music is risky but has no direction
People saying "no" are obviously pressed their faves have never (and won't) been called the "vanguardist of Pop".
Yes, Britney Spears is Pop's trendsetter. Her albums are always ahead of their time and manage to slay. Blackout is the masterpiece that introduced the world to a new genre; Hold It Against Me's use of dubstep (and she had already used it in 2007) slayed and was so risky.
The only time Britney Spears wasn't risky was in 2000 with her "Oops!" album and perhaps "Circus", but "Circus" gave us jams and a more mature Britney that the audience wasn't used to.