I'm sure normal rubber will give better road feel, as RFTs can dull the steering responses.
I must say, I'm pretty impressed with how my F11 is steering and riding. I'm on 18" Continental Sport Contact 3 SSR tyres. I don't think I'll be changing to non run-flats as I did in the E91. But do feel there would be at least a slight improvement to steering responses, and a little more ride refinement with normal rubber. Simply due to the fact normal rubber hasn't got the negative characteristics of the run-flat. But at least in my setup, I think BMW have done a pretty good job of either masking, or refining RFT behaviour. I don't think changing rubber will give the drastic changes that I found on the E91, we have moved on quite a lot, IMO.