I tried to make this very argument with a former employer. Who cares about numbers except for weird technical people? Just pick a cool marketing name and market the heck out of that that. "But we've always marketed 2.0 or 3.0..." So what? I suppose there's a small psychological benefit in a monotonically increasing number, but it doesn't really tell you anything more than "Saucy Gorilla" in terms of what is in a release. It can help you order the releases if you need to know which release came first, but you can alphabetize your codenames or even just have a lookup table for those rare times that actually matters.