Tilt Rotors have less payload (given the same power and empty weight) and are not as nimble at low speed. Those are facts, much as we might try to wish them away.
Generically, I dont think you can say that tiltrotor payload is always less for a given power unless you specify a mission or some parameters. The ability to perform STOL maneuvers means that you are not necessarily limited to rotor/hover performance for payload calculation.
For low speed maneuverability, ADS-33 is a pretty dated spec, and new tiltrotor designs seem to have designed remedies for the V22 yaw sluggishness with much higher flapping capability.
Nick, weren't you the one chiding Weiner's team that if they wanted to hit their speed target on X2, they just needed to push it out of the ramp on a V22? But that was in your Bell days
