I have to agree with you, I have had automatics
that were reliable about kicking down quickly when punched. (except when you threw them a curve ball by cycling up and down, and then catching them at the wrong time)
Sounds like you got the standard dealer hand holding when they know ahead of time that it is what it is.
Face it, probably most modern day BMW buyers are not exactly wanting razor edge performance with their auto. They'd rather think their machine is race heritage, but mostly make trips to the grocery store.