Kanye's performance lasted about two hours. That's either a good or bad thing. Yes, audience members were treated to more than their fair share of 'Ye's glowing presence, but they also had to sit through some odd interlude transitions. There were also moments where Kanye would lay on the stage and not get up until the next song came in. Maybe he was exhausted, maybe it was part of the act. Either way, Kanye lost some of the audience's energy.
Similarly, Kanye forgot quite a few of his lyrics when performing some of his older songs. Again, this may have been due to fatigue, but there were clear moments where he stopped rapping altogether on "Heard 'Em Say" and "I Wonder." On "Through the Wire," he didn't even rap at all and instead greeted fans that were near the center stage while the instrumental played. It made for an odd showing.