John Groce was bad. Fear of a John Groce repeat isn't a good enough reason to keep a coach.
Bill Self is a superstar. Until Illinois gets a coach of his caliber in here fans will be calling for an upgrade.
In no way is Brad Underwood in the superstar coach tier where people like Coach K, Dean Smith, Roy Williams, Tom Izzo, Bob Knight, Lute Olson, Rick Pitino, John Calipari, Bill Self, Jay Wright sit. All of those I listed have a natty (7 have 2 or more), 4 or more final fours, 10 or more P6 conf. championships, win % > 70% at P6 school, conf win % > 70% at P6 school (except izzo and wright), and 8 or less years at a P6 school to reach first final four.
Is Brad at the next tier down, the Thad Matta, Bo Ryan, Matt Painter tier? Maybe, though his career achievements aren't as good as those three and he's older than Painter and Matta. But until you've found a superstar coach you don't stop looking. And if you want to fire Brad, show me some freakin' names, and put their last 6 years of accomplishments against his side by side.