[Z]

I think the generally accepted view is that Keisha is a workaholic and after Mutya bailed on them mid campaign, they stopped pretending that they all had an equal amount of input into lyrics and the creative process. If you look at the writing credits for Change and Catfights & Spotlights (especially the latter), if there's any input from the band then it's almost always solely Keisha.

Amelle and Heidi clearly got sick of her being a control freak, and Amelle couldn't handle being famous (see: night club fights, convictions, drink driving, not showing up for work) and it was becoming clear that she was going to leave the band either way; Keisha tried to get Mutya back in the band (with both complimenting each other in the media and Mutya even saying she'd love to be back on stage with them again in the days leading up to Keisha getting the boot) but Heidi hated Mutya for leaving them and never speaking to her again - reports of Jade Ewen joining the band were rife in the days leading up to it; but they were trying to break America and Amelle was being pushed to the front as the leader of the band; Keisha got threatened and it basically turned into it's her or me (on Amelle's part; Keisha didn't seem to have a clue her job was in jeopardy); and Heidi chose Amelle and that swung it.

Either way, the record label had a music video to shoot, a single to release and an album to promote, and Jade Ewen was getting a job either way. Heidi just chose the person she felt closer to at the time. They then did a very passive-aggressive hatchet job on Keisha, saying they "couldn't talk about it" and "bullying is a strong word" etc etc, but I genuinely don't believe Keisha is a bully. Perhaps when it was the original Sugababes, but they were teenage girls with hormones flying everywhere. I absolutely do not believe for a second that Heidi thought Keisha was a bully for 8 years and never once thought to speak up about it or leave the band. If she really thought Keisha was a horrible person, she would have left when Mutya did and the band would have ended.