It seems that nothing has changed besides that the console is HDMI only.
They also seemed to have shifted the powerbrick outside again making it a tad smaller.
It seems that the current RGH and drive hacks (Flash/Xkey and replacement PCB's) still work.
MS hasn't changed much on the Motherboard it self and the DVD drives are still from Liteon.
*THIS STILL NEEDS TO BE CONFIRMED*
More information and a full tear down + pictures on iFixit.