No matter what the reviews of this year's Super Bowl halftime show ended up being -- and they were mixed as always -- the lineup alone showed some serious shaking up of the annual event is essential to keep it interesting.The obvious issue this year, for what should've been a landmark event as it was the 50th Super Bowl, is that the headliner was Coldplay, who, like them or not, have the ability to generate fist-pumping excitement as much as a glass of warm milk before bedtime.