If you, like many fans, believe Diaz won the fight vs Condit, then this fight is the fight "which should be taking place".
Who people believe won the Condit/Diaz fight does'nt matter. Diaz lost to Condit and Condit lost to GSP. The only person that should be fighting GSP next is the fighter who has earned it, currently this means it's Hendricks. Everyone else has to work their way back up to a title shot.