Honestly my '08 328i feels that way too, but I think it's normal. No difference in 3/4 throttle vs full throttle, and when I slowly let off the pedal, it seems to continue to pull the same as it did at full throttle right up to about 1/4 throttle. I think the throttle mapping changes depending on what gear you're in.
In my 6MT, first gear throttle is very mushy and insensitive. I think that's to help the driver have a smooth start. In the higher gears, the throttle is much more sensitive and it's those gears where I don't feel much difference from 1/2 throttle vs full.
Perhaps your car had adapted to your driving style and lost those settings when you disconnected? Just a stab in the dark...