Optical media has proved to be an issue, even the Xbox consoles in an update specified a "fix" so older consoles could read a little bit more data from the newer games as the image was slightly larger. If games started to use flash based storage, it would do many things, one, allow people to save to the game cartridge once again, two, bring prices of flash media even lower, three, faster read times. But, I don't see them doing it, unless they come up with a system that is difficult to connect to the PC. Cartridge consoles usually have pirated games up the day of release if not sooner, I don't think Microsoft or Sony would enjoy someone just plugging a cartridge up and downloading the game data. So we would be back to proprietary data storage, though, it would be worth it.
Could have sworn I read an article somewhere that piracy (consoles) is in large part because no one feels the desire to pay $60 for a plastic disc and get almost nothing these days in terms of game play-ability.
But yea, rumors of the PS3 are pointing to them using a rather similar GPU as the Xbox360, I think what will make the machine is storage options, and raw processing capabilities, along with making it simple for developers to move to a new console. The downfall of the PS3 at start was the CELL processor never being taken advantage of entirely, and sony even locking cores to specific functions.
If Sony and Microsoft wanna keep these consoles with high prices and games with high prices, while making the console a full "entertainment" system, they NEED to get to work on codec and network support for these consoles. It is sad when the community has to build transcoding software so these consoles can easily browse a full media library that is composed of hundreds of different types of video. I treat my 360 as an HTPC at most, I rarely game on it, only purchased it for halo, and later on after discovering PS3 Media Server turned it into a simple HTPC, but limited codec support made that alone difficult.