First of all, whatever theory is most correct, no-one says it only has to be one single effect causing this phenomena.
Whilst rotating and lifting off and going from zero lift to enough lift to accelerate the aircraft off the ground, several things happens almost at once.
In the end, though, all is down to Newton and his inertia as well as acceleration laws. Whatever molecules are accelerated downwords gives lift, whatever molecules are accelerated rearwards gives thrust, and that is the end of it, really. Drag and counterproductive lift works against thrust and lift, like the side effect of induced drag makes some of the molecules accelerate upwards. Closer to the ground, this effect is reduced by the ground blocking the rotating moment of the slipstream, ground effect of course. The ground effect is yet another hot discussion, ranging from "a pillow of air", deflected downwash, tilted lift vector etc, but again the end of it is the fact that the sum of acceleration of all molecules determines the acceleration of the aircraft.
If we look at the pitching moment only, these shold be the factors able to influence it:
1) Amount of lift (as center of lift is not colocated with the CG)
2) Center of pressure moving fore/aft
3) Downforce produced by the tail
4) Maybe the CG, as the aircraft tilts aft, gravity works on CG at a more rearwards angle, but this might not be significant. CG should be the same, but the direction of the force acting on it changes.
Factors not influencing it in this case
Gear/flap retraction (since we are only talking about the rotation itself)
So, wrong me if I am correct ...