Any software project that requires its users to constantly file, "Hey, you broke this" bug reports is a failure, in my opinion. It's a double failure when the project ignores its users pleas to, "Hey, quit breaking stuff!"
The solution is so simple: don't replace working code with broken code. "But we need people to test it!" you say. People will still test it if it's called alpha or beta. It will take longer to reach parity and maturity--but so what?!
I wish desktop devs had a mindset more like Linus's: "Don't break userspace, EVER!" How about, "Don't break existing functionality, EVER!" (i.e. don't release it until it's working and equivalent).