What would be the advantage of doing it that way instead of just putting the motor on the car frame and connecting it to the wheel with a CV axle? From what I could dig up, mechanical losses in a CV axle are on the order of 1%.

An active suspension requires power, too. And a heavier wheel would presumably require a more power-hungry active suspension than a lighter wheel, so you're not getting something for nothing in terms of efficiency.

I guess it is a matter of numbers, though. A CV axle also gives a wheel inertia, as it has mass and moves when the wheel does (partially). If you can make an insanely light motor, maybe you could make it so light that it's actually contributes less inertia than a CV axle would, in which case go ahead.