Trinidad-born, Queens-raised, Fame high school-educated Onika Tanya Maraj took the music world by storm in 2010 with her debut album Pink Friday, which followed a series of wildly inventive, genre-defying mix tapes, and introduced the unlikely hybrid of Missy Elliot eccentricity, foul-mouthed Lil’ Kim provocation, gangsta fronting and sexed-up Kewpie doll flirting better known as Nicki Minaj.

Why an artist who’d already engineered such an elaborate, chameleon-like persona would choose to invent yet another alter ego with the inscrutable name of “Roman Zolanski” remains a mystery; was she trying to evoke notorious statutory rapist Roman Polanski? But an even bigger question is how the extreme diversity that seemed so fresh and effortless the first time around has become so forced, annoying and unfocused on the encore.

One reason is the everything-and-the-double-vanities excess: We get no fewer than 19 songs in a total of nearly 70 minutes, produced by a wide array of up-and-coming sonic craftsmen such as Dr. Luke, Kenoe and Rico Beats (some more imaginative than others), and featuring a long list of often distracting cameos by the likes of the star’s mentor Lil’ Wayne, Rick Ross, Nas, Chris Brown and Beenie Man. But a bigger factor is that Minaj has added yet another ingredient to her already complex Trinidadian stew: a hefty heaping of sugary pop that attempts to split the difference between Katy Perry and Madonna (whose spotlight she shared at the Super Bowl), via pathetically pandering, syrupy-sweet suck-ups to the American Idol universe such as “Young Forever,” “Marilyn Monroe” and “Fire Burns,” which dominate the second half of this long set.

And this despite the singer’s protestation on “Roman Reloaded”: “Nicki pop?/The only thing that’s pop/Is my endorsement ops.”

The pop turn isn’t the only misstep, however. If part of her goal was to assert herself as a powerful, independent woman, as she’s done in the past, Minaj fails miserably here, from her unthinking and unjustifiable fondness for the word “bitch,” to the excreable closing track “Stupid Hoe,” to the bizarre and endlessly repeated threat to “Put my d--- in your face,” all of which play as cheap, offensive button-pushing closer to Odd Future than the proud lineage of female rappers she brags of “putting back on the map,” Elliot among them. Sista Souljah she certainly is not.

Musically, the unexpected, even jarring stylistic leaps that once were so much fun have become a stone-cold drag; witness the effort to shoehorning a chunk of “O Come All Ye Faithful” into the robot dance ditty “Roman Holiday.” And what’s with that weird, nearly unlistenable Cockney-accented singing? Imitating Rhianna is one thing, despite the fact that Minaj can’t sing. Channeling a reject from a high-school production of Oliver is another.

Taken as a whole, all of these missteps and demerits overwhelm the scattered charms of Pink Friday: Roman Reloaded, chief among them Minaj’s odd rhyme schemes and nimble flow. Even in this golden era of self-obsessed superstars desperate to provide something for everyone, you’d be hard pressed to find an example of anyone in greater need of the ability to focus, self-edit and learn to distinguish her strengths from her (now all-too-obvious) weaknesses.

Nicki Minaj, ‘Pink Friday: Roman Reloaded’ (Universal Republic)

Rating on the four-star scale: 1 star.