Backwards compatible: No
raytracing support: No, or on an insanely basic level
SSD standard: Nope
but it's official from Cerny himself
Take a look at the original PS3 shown in 2005 vs. the actual PS3 that came out. No dual HDMI, no 120 fps, no dual 1080p, no network hub. The first "reveal" of Sony systems ALWAYS have tons of features to portray power, and then strip them out over time. Let's wait till the actual announcement to see what we actually get, not what Sony is BSing about pre release.
Also, there is zero confirmation that BC won't be locked behind a paywall of some sort.