I think people are reacting too much on a williams win. They already were very very fast in Melbourne, and had both cars in points positions in a rainy Malaysia and in China. It was only Bahrain when they were poor. This is from a team that's been critisised for not employing drivers for their talent, on a pretty tight grid. Sauber isn't a bad car at all, and the main reason they didn't get a stronger finish in spain was Perez's tangle in the start.
If you don't like that the person who has the most switched on tyres wins, well, then you won't like Hamilton in rainy/damp 2008 either. Or McLaren in damp conditions for the last two years. The truth is set-up has always been critical in F1. Progress means we notice less of it today, since teams get it much better from the get go. Montoya once said that if you got it wrong, you'd look like an idiot that's 1s/lap slower than his teammate. Look at Button and Senna last race. Or Massa for almost the whole season. It still applies.
This year's pirellis are quicker in qualy. They are also quicker for the race... provided that you regulate their life. Is it really such a lottery that in a grid where 0.5s separate about 10 cars the person with the better setup gets a brilliant result?