Uli,
I don't think it will matter. At the end of the day, smoothness counts. On the BMW, the rain mode will smooth out bad rider input, but you can still have poor throttle control and it will affect the motorcycle.
I have had thoughts about this for a long time. For example, imagine a motorcycle that would graduate you to higher and higher speeds rather than let you open it up on a track. Therefore you slowly worked your way up and could focus more on body position, throttle control, and braking. Instead of charging the corner, you had to plan for it. And I thought the magic answer would be a motorcycle with a governor and a GPS, which might allow you to make 1-2 mph improvements over your baseline each lap. But then I realized we have something like that... 125s and 250s. Not to mention a technique, such as riding in a higher gear like 3rd or 4th.
I the case of the BMW, I run considerably slower in Rain Mode on the BMW. Part of it is because I can't accelerate out of a corner as fast as I'd like. The TC comes on pretty quick. It also softens the inputs. However, I could still send in bad inputs and it would overload the tires, or panic brake. TC and ABS can let you get away with some things, but they don't solve the problem of bad input.