You are looking at this the wrong way. If your baseline is VTOL requirement, the motors have to be sized to enable vertical climb and additional power for control movements. Then you have to look at next how to make it more efficient and more socially acceptable than a helicopter. No point at comparing it to fixed wing aircraft that cannot take off vertically. There will be a flight distance point beyond which tilting rotors and wings will be beneficial. Vahana is exceptional in sharing their experiences. This is the way of the future, not shrouding everything in secrecy. They've done these studies. For the comment that tilting the rotors "will not do", check out their flight test:Hi Kingfisher, great for sharing your work!
I think the biggest problem for VTOL aircraft design is the disparity in power between hovering and cruising. This VTOL conundrum is somewhat alleviated by the high efficiency of electric propulsion, but the lift in hover still needs to be increased without consuming much more power. Just tilting the rotors will not do; e.g. for a cruise L/D of 10, thrust needs to be increased 10 times for VTOL operation, and power rises even more, exponentially. Designing the aircraft for efficient VTOL operation, low disk loading is needed, leading invariably to large rotor disk area, which is detrimental to efficient cruise operation. Having the wings in the rotor's slipstream they are just dead weight, even worse they consume energy as boundary layer friction. Some gain can be achieved by putting them in front of the rotors, as here: http://aliptera.com/development.html#Lip Wing