Sadly, the PlayStation 4 will not feature backwards compatibility (at least, not in the truest sense of the term; i.e., owners being able to put actual PS3/PS2/PS1 discs in the system).
That's annoying for many gamers, especially because this generation has lasted quite a long time and chances are, we all have pretty hefty backlogs. That really can't be helped and upcoming cross-generation titles won't alleviate that frustration.
However, given that we can anticipate so many blockbuster cross-gen games for this particular console transition, not having b/c doesn't seem quite as painful. It will also prompt more early adopters of the new platforms, because they have fewer reasons to hold on to their old systems. This year, it's very possible that the biggest games on tap will be available for both current- and next-gen platforms, and that should be viewed in a very positive light.
It has been confirmed that Watch Dogs , Assassin's Creed IV: Black Flag , and now Call of Duty: Ghosts will release for the current batch of consoles, as well as the PS4 and new Xbox. Furthermore, many are already getting excited for pure next-gen titles like The Witcher 3: Big Hunt , Thief and inFamous: Second Son . More will undoubtedly be unveiled at E3. Combine that with the possibility that Battlefield 4 and Grand Theft Auto V might also end up being cross-gen games, and you've got a more agreeable situation in my mind. It makes for a less abrupt switch.
I don't really know of many PS3 or Xbox 360 games that I'm really going to want after the PS4 and Xbox 720 come out. Do you? Beyond: Two Souls is set for October 8, and that may indeed be the very last PS3 game I ever play. Beyond that, everything I want should be on the next-gen systems, and that makes the console transition a lot easier. Besides, as time goes on, backwards compatibility becomes less and less of a deciding factor. Me, I'm thinking about just having my PS4, PS3 and PS2 all hooked up so I can play any PlayStation game ever made whenever I want. 😉