There have to be at least three, maybe even four, of you out there who want full screen Flash playback on the PS3. Firmware version 2.53, supposedly available tomorrow, is the firmware for you, then, as according to CVG it adds just that functionality.
Having already seen an upgrade from the previously horrendously outdated Flash version used by its browser to Flash 9, in Firmware 2.5, the revision isn't exactly surprising. It is a little strange that the feature wasn't there already.
As great an all-round device as the PS3 is, though, I doubt that many people use it for the web browser. And of those I expect even less watch many flash videos - as addictive as watching Charlie the Unicorn on the newly-widescreen YouTube can be.