It may seem that way, but I HIGHLY doubt it. Riku and Sora are like Vegeta and Goku, or Dante and Vergil, or even Sonic and Shadow. It seems Riku is always trying to stay a step ahead of Sora, trying to be the best. The probably the only reason he has such a close relationship towards him, he's lust to be the best, just like Sora. But Riku doesn't have that with Kairi, but he knows that she must be protected at all cost. And as it shows, both of these warriors fight heart and soul to do that. But when it all comes down to it, who is the better man for her?
All those who show true wisdom, will live to see the wonders of the Kingdom, Hale to the King Of Games. Join Team "Royal Kingdom$$$$"