I suggested at a parallel between the two on here a looooong time ago and basically got flamed for it, but look where we are now - Villeneuve was forgotten just like that, 5 minutes after people were hailing him as a 'future legend' when he passed Schumacher round the outside! I don't think Hamilton has to prove anything new, just fulfil the 'easy' task of meeting his (sometimes absurd) expectations!
I think a harder task for any World Champion is to try and defend their title the following year. However, Hamilton's task will always be harder than the average for one reason - He's British. The British Media can be your friend and your enemy all rolled up into one. Such expectations are placed upon Hamilton by the media, even though at this point he does not have the machinery to be World Champion. For those who have no real interest in Formula One, opinion of Hamilton can easily change on briefly seeing that he isn't doing very well. That's the fickle Uk Public for you.
In terms of the users on this board however this isn't the case. We base our opinions on the true facts (or for some blind patriotism).
End of the day Hamilton is a great driver. I have never denied that and believe he has the potential to be one of the greatest. However the same goes for the likes of Vettel and Kubica in my opinion, both of whom have done amazing jobs in cars which were never of the level of Hamilton's. This will be a telling year for Hamilton - but so will every single yar of his career. Face it if he doesn't win the title this year people will labell him along side the likes of JV etc. If he does however people will ask, can he match the likes of Schumacher? The expectations are too high for him sometimes.