IMO I think the clouding/flashlighting issue is more of a "recent thing" - in the sense that, 2 years ago (2007) it was relatively minor (perhaps due to very stringent QC) and nowadays it's much more prevalent (perhaps due to cost-cutting in the QC department).
My own anecdotal evidence:
KDL32-S3000 purchased Dec. 2007:
- although black levels are pretty crap, the viewing angles are poor, and the contrast is pathetic compared to most year 2009 LCD TVs, there is NO flashlighting or clouding nor has there ever been any! I used to watch a lot of 2.35:1 aspect ratio movies in the dark, at night, so please take this as gospel
KDL46-W5100 purchased Dec. 2009:
- black levels are beautiful, viewing angles are much improved, contrast is much much better; but
I have minor flashlighting (albeit no clouding). Compared to other people on this forum, my flashlighting is not that bad and it's not worth it for me to exchange (since I might get a "horrible" set belonging to one of the other guys here, LOL).
However it's a bit of a "shock" for me as I'm used to an LCD TV with ZERO flashlighting so having one with a small amount is still noticeable, especially when I'm watching 2.35:1 movies.
I was able to mitigate this slightly by performing the following:
- rubbing the screen with the microfiber that came with my "LCD TV Cleaning Kit"
- repeatedly showing a FULL BLACK and FULL WHITE 1920x1080 jpg file on my TV through the Bravia Photo Viewer
- turning on the "ambient light sensor" in the Sony's ECO menu
I don't know which one of these helped the most since I sort of did them all at once. :/
Chances are, it's the ambient light sensor which is doing the most help.