Hi Paul, I felt the same moving from a 350 to 370 and could not understand why, it did not feel as sharp or throttle responsive.
That was before I read and realised that Nissan made the throttle pedal travel longer on the 370 to make it smoother to drive.
Once you get used to this and use the full extent of the 370 pedal travel performance is significantly better on the 370 but much smoother to drive around town.
I do not regret in the slightest moving to the 370, it is a stunning car.