It has BD-drive, meaning that drive itself should play basically any optical media (excluding HD-DVD). It's then all up to the software what it accepts and what it can use.
I would actually see PS2 compatibility being really good selling point for some. After all, that system was so widespread it's hard to not find games for it even this day and many may have huge library available. Then the fact that PS3 didn't have backwards compatibility so legit ways to play those games are really limited to mostly second hand stuff. Playing those games with similar more modern controller with HDMI output and possibility to record the gameplay? Also at this point, I would say that PS1 compatibility should be childs play to implement for them and that would be really good customer end feature as they are also selling tons of stuff which is compatible with PSP, Vita and PS3 already.
Because even now PS4 lacks TONS of features that PS3 had to make it viable living room center piece. At least having it to play tons of more games, even if they are older ones, would rise the value of having that machine. Nintendo and Microsoft have already gotten this, even though Microsofts emulation isn't up to the par.
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