As disappointing as this is, I'm actually relieved that they're not pushing out another version of what we have now. To be honest, if they keep to tweaking the Playstation 3, they can get maximum punch out of it, which'll be great for game dev's who'll be able to push their games to the Sony audience. If they brought out another console, the PS3 would die, just like the PS2 when the PS3 came out. Additionally, if they began to focus on the PS4, they'd very probably totally abandon work on the PS3 and the PSN because of it, and the PSN isn't really in a time frame to stop work on right now, what with the downtime we had in August, which it's still recovering from..I believe.
And really, once they begin to look at developing the Playstation 4, all they'll have to do is keep the style they've kept with the PS3, possibly making the case look better (The feel of the slim's matte case isn't particularly 'stylish' looking), and packing in that extra RAM, and that's good enough for me. :p
When it comes to 3D gaming, however, I think it's gonna be a while before stacks of consoles take it on board, as the feeling of wearing bulky glasses whilst ripping it up on CoD just doesn't feel right - they'll fall off within the first sixty seconds..with me anyway.
Though it sucks that they can't bring out another console for me to blow a grand on, it's gonna be good in the long run not only for the PlayStation 3, but for the PlayStation Network and the Sony company in general. Not so much stress on what the staff already have on their hands.