I'm personally very interested in the "Low Power Island" and it's efficiency cores for it's efficiency cores.
S0 standby is pretty rough on high end high power laptops like my Thinkpad with it's 11th gen i9. I sometimes have power drain higher in standby than just normally on. If Windows is smart it could turn off all cores but the E E-cores and maybe make modern standby not so much worse than S1-3 standby.
The Low Power Island also has DLVR finally, but sadly the rest of the CPU doesn't.