Everybody says they don't like the yearly updates, and by "everybody" I mean the few hundred, perhaps even a few thousand people who post on blogs and forums. But the reality is that when any software developer chooses to stretch the release dates and don't add new features, people complain that there's nothing new and no reason to update. They can't win.
The other reality is that 90% of what people here (and other forums and blogs) call "bugs," are just conflicts or issues with their own particular computer setup. While that could be partially Apple's fault or developers of other apps, it's almost always the end user. True bugs can be reproduced on anyone's computer. That's not to say Apple doesn't ship with bugs in the system, that's unavoidable, but it's not nearly as bad as people make it out to be. By shipping updates often, they hear about and are able to fix bugs faster than if they only shipped every few years where technology moves on and app developers get tired of waiting for Apple to implement those technologies.