The new DLSS 4 framegen really needs to be much better than what's there in DLSS 3. Otherwise the 5070 = 4090 comparison won't just be very misleading but flatly a lie.
As always wait for fairer 3rd party reviews that will compare new gen cards to old gen with the same settings.
Not necessarily. Look at the reprojection trick that lots of VR uses to double framerates with the express purpose of decreasing latency between user movements and updated perspective. Caveat: this only works for movements and wouldn't work for actions.