If this was a characteristic of LCD's, has this been a big problem for other manufacturers over recent years ?
Indeed it has, hence articles like
this one and the numerous posts concerning the exact same problem with Panasonic LCDs earlier this year.
Don't get me wrong, I personally think some of these clouding issues are unacceptable, but unfortunately, the manufacturers seem to disagree. My point is, it isn't just this model which has the issues, or even just Sony. It just seems that this is the model everyone is talking about at the moment, presumably because on the back of various awards, it's one of the most popular. I agree with you though, the clouding issue is pretty serious when you enjoy watching films in the dark, and is one of the reasons I went for a plasma screen.
I think someone else said it best on another post when they had an issue which the manufacturer didn't class as faulty as they had a few dead pixels. In the end, their retailer swapped it out for a new model even though they didn't have to because they knew the value of good service to the customer. This just enforces getting a good relationship with your dealer and buying from them rather than going for the lowest cost, worst service option.