I've heard that argument before...and I can see the logic in it...but
When I think about that scenario, this is what I think of...and these are the things I considered before deciding to go with a cut pan:
-The slope is there wether the pan is cut or not.
-The oil is very high in the engine in relation to the pickup. If you don't count wheelies (I don't wheelie), the oil has to be at a rediculous angle before the pickup is sucking air.
-When oil moves backwards in the pan (like when under hard acceleration), the slope at the back of the pan and the low nature of the pan keep oil forward because the total volume is less inside the pan. Take 2 engines, one with a stock pan and one with a cut pan. Tilt both rearward, the oil in the engine with the cut pan will be closer to the pickup (until the oil drains into the tranny anyhow).
-I've seen guys wheelie Hayabusa's and GSXRs with stock oil pans at nearly 12 o'clock for multiple city blocks without spinning bearings.
mind you, Motorhead has more Hayabusa experience in his little finger than I'll ever have