A bunch of reasons, or so I read. They wanted to make a big change to shake things up and mess with the boring rut the show's been through, and killing anyone else from the main cast would've been too much. Brian was their sacrificial lamb... dog, but it's Family Guy, so they can always bring him back when they want to.
I heard Seth's tired of making Family Guy episodes.... :( And he did it cuz he knows people will lose interests if he kills one of the main characters... :'(
to make drama, and stewie will build a new time machine becuase the arab guy will miraculously and ridiculously have a reason to sell the plutonium or wtv it was and all with be back to normal...
WHAT? THEY KILLED BRIAN? NOOOOOOOOOO. WHY NOT CHRIS?
Lack of viewers. He'll be back once they rake in enough millions. Should have been Meg though....
Im sure he isnt gone completely. Just like Cleveland, he will have random appearances every now and then
everyone wanted him gone
you were in on it the whole time, werent you???
I want my lawyer!!!