He's cool. I blame the producers, they're the ones who set the time limits and probably make it clear that the limits have to be followed, and judges like to go on and on, so he has to curb them.
He's still cool in my book. I hope he doesn't get replaced.
EDIT: Actually, here's some proof to back me up:
"And if I can't get an answer, then she abstains, and I move on. That's the way that the show works. But I got like five producers screaming in my ear, 'Steve, we need an answer. Okay, she's not gonna answer, move on. No, wait, she is gonna answer. Move back!'
"And chuck Simon Cowell into the mix going, 'Back off! Leave her alone.' Whoa, everybody's giving me major, major abuse here from both inside my head and outside my head." http://www.digitalspy.com/tv/s141/th...to-choose.html
A good host is supposed to easily transition what needs to be done, without coming off as rude or arrogant which is exactly what he doing. I don't care if there's 5 producers screaming in his ear, it's his JOB to get what the producers want to be done in a charming and nice manner.
