Sans,
I suspect when Nick is referring to lower payload for the same power and empty weight, he's referencing the higher disc loading tilt rotors have always had (at least up through the 609 and Model 916/918 aircraft). The V-22 has famously poor disc loading (wing/blade fold being a huge design driver), but even the better balanced 609 is still higher than an X-2 would typically be.
Looking at the V-280 concept art, it does appear that they are looking to improve the disc loading and thus hover efficiency over the V-22, but I doubt they will get down to ~12 lb/ft^2 like the RAIDER (and presumably SB>1).
None of the tilt rotor heads that I have experience with has a dramatically higher flapping capability than the V-22. Certainly the two production intent designs flown after the V-22 don't. So if there's enhanced low speed maneuverability, it isn't coming from there. In VTOL mode, these aircraft are very G limited vehicles until they get significantly wing borne.