John Rutsey was not fired from Rush, he just was not as serious about becoming a musician as the other two in the band, he would later comment on how his leaving and watching Neil on the drums cemented his thoughts about being a musician and the music world....
Mick Pointer was indeed fired by Fish, for being amatuer-ish
Paul Dianno was too immature during his time in the band, and when he was fired from the band, the band's mometum was rising
Doug Ferguson left Camel, when he felt the music was becoming too complex for his liking...Andrew Latimer often lamented that Doug's leaving had catastrophic ramifactaions on the band afterwards....
Andy Ward was asked to leave Camel in order to get his life back in order, the few years after Doug's exit, Andy was abusing drugs and alcohol to the point of his usual stellar performance had suffered severely...
Peter Banks was also dissatisfied with the orchestral hinderance of A Time and Word, and he was fired by Jon and Chris when his bickering became too much for them to handle...
John Mayhew was by Genesis for being too much like the band during their sessions for FGTR ...Meaning that John seemed more "wide-eyed at the fact that he was in a band and performing in front of crowds...
Steve Hackett had to be coaxed in to not leaving Genesis after the Foxtrot sessions because he felt as if he was being underappreciated
Charles