I don't think the Girls Aloud comeback is up to any of the girls, it will all depend on what the record label wants, and honestly, I don't think they are much interested about it. There are five memebers in Girls Aloud, so you have to multiply per 5 all the expenses; royalties, stylist, transport, accomodations, and a huge etc. It's far more expensive. With Cheryl they get really good results without having to do any big effort, the promotion she gets is far less than what Girls Aloud used to do, and she stills manage to get better results.
A solo artist is easier to sell than a girl band, and also, Cheryl's music is more urban, a sound that nowadays is more consumed than the pop path that Girls Aloud used to follow. I can't see why would they want them back together (unfortunately for us).
"5 problems, 1 solution."