You've conflated two separate issues (Vista the OS and Vista's launch) so it's hard to argue accurately about this. I think you're using a too-broad definition of launch if you can offer improved search as evidence of a successful one.

I would agree that Vista is an upgrade in the same way XP was: moderate improvements with new UI things to learn. And I think you're very right to refer back to XP's launch and how the same complaining was made then.

But I don't see who you can call Vista's launch a success. This would probably be better debated with empirical data about sales and time on the market and stuff, but just the general vibe about Vista is so horribly negative in ways I don't remember XP's ever being.

You say this is because more people are making their negative reactions known this time around, and we should ignore them because people like to bitch. But I don't think it's a forgone conclusion that their reactions would be negative -- they could've reacted positively.

I doubt Microsoft is proud of Vista's launch.