All of the Lights: Would it have smashed? The most commercially appealing Kanye song in a long time. If he had given the whole thing to Rihanna, she added verses and she chose to use it, would it have been a smash single? The chorus is so damn catchy, and it fits her perfectly.
Its kind of feels like a Rih solo, but the song can never be a Kanye solo either because all of them (Kid Cudi, Fergie, Alicia, Rih... ) make the song what it is...
Hell no. The song didn't do well because radio was flooded with Rihanna at the time! If it was a Rihanna solo it would have flopped so hard... The hit was in the fact that it was an ensemble of so many great artists and that it was a perfect pop song. If Rihanna hadn't had two songs in the top 10 at the time of AOTL, the song would have blown up far more.
Plus... lets be honest, the song would be nothing without the other artists. They make it something special and elevate it to pop perfection.