You're talking about different things.
Since changing the spark plugs, my hesitation around 2500rpm has gone away.
However, the awful electronic throttle has a deadspot for a centimetre or so (feels like way more) before it actually does anything, then it suddenly comes on FAST. Apparently some are better than others. Mine sucks. If you push the deadzone at idle, you'll find it does lift the idle, so it does SOMETHING, but obviously not enough to feel like anything more than deadzone on the move.
Stupid stupid BMW. I hate the throttle in this car.