Tom775257, what you are proposing is analogous to lowering the flaps at the point of rotation. This will indeed increase lift but may also induce a pitching moment, either nose up or nose down, which could make the aircraft very unpredictable/difficult to fly just as it unsticks. However, you could have control laws which automatically give an elevator input to counter this pitching moment. As safetypee says, an elevator interconnect with the DLC spoiler deflection works on some aircraft on the approach. However, trim changes at rotate and unstick are more critical as you have to allow for a misset trim (incorrect AUW and c.g. on loadsheet!) and the discontinuities due to wings, tailplane etc being in ground effect.