While it is highly possible that PS4 will play the PS3 games, with the ablity to play blu-ray movies and such...but I dont think it may have the chance to play PSone/PS2 games anymore on the PS4...obviously due to the cost of manufacturing. But let's see.
PS4 sounds like another revloution of videogaming, and I sure as hell am looking forward to the future of the Playstation universe.
As for the PSP2, it may definetly be possible that we might play some PS2 games in the future.
There are some things that I dont like about the PS4...saying that it may still support HDTVs, but will actually support Quad Full High Definition (aka SUPER HDTVs) in 1440p, 2160i, and 2160p. I dont think I would really be able to afford a new type of an HDTV in a long time since my current HDTV works just fine and I bought it 4 years ago. Another thing is that the PS4 dont really seem to support componment...only HDMI. That's not good for me because my HDTV do NOT have an HDMI. only componment, composites, VGA, and DVI. I can only hope I can still allow componment on PS4.
The PS4 definetly sounds MUCH more powerful than I thought...in my opinon it seems abit too early trying to get the PS4 into more powerful HDTVs that support into resloutions more than 1080p...ugh.
The future looks cool, but seems pretty much more expensive.