I really took it gradually as I went from 7-11mm to 4-8mm over about five years time. Every time I took off another millimeter it all gotten better. With better playability there is better sound. I don't feel that I'd have lost any power and I can dig in if I want to. I can use more finesse in shaping the sound, and play with less fatigue. The bass growls if I want it to, and moves air just as good.
Just because its a big double bass, it doesn't have to be hard to play...