According to the official specs, it will have a Blue-Ray drive, so yes it will play games on blue-ray.
And the second one is also false. Single player and MP is determined by the game developers not Sony. Sony just provides the hardware and network for them to use.
It's all about the social nonsense. You're sharing a game with someone else. Sure if you're 12 but if you're over 20, not so much in demand. I am a gamer. I will buy and pay good money for well developed games. Not some hack creating junk that will hickup until it dies. Not interested. Playstation 3 and the older games will be just fine for years to come obviously. Too bad. I bought the Playstation and then Playstation 2 and the Playstation 3. Backwards compatibility not required? Some marketing guru thought that one up because they couldn't wait for the developers to provide a solid compatible environment. Shame on Sony.
Got the money. there just has to be good enough games at launch otherwise what's the point in buying a new system on day 1? Back when the ps3 came out I got the Motorstorm 80 gig bundle and I also got Resistance and a couple other games. I still remember playing Motorstorm for the first time and being in shock that a game could look that good. Now if I were to play that game again I'd probably think it looks like trash lol. I want that same kind of feeling when I play a game on the ps4 for the first time. Destiny looks really good from what I've seen of it.