Very interesting post,smaller lower powered cars do actually feel better with a manual box and auto's in those feel sluggish and unresponsive while on the BMW diesels or any diesel for that matter auto is preferable over Manual any day.
I had a manual 320d that I changed to an auto 320d just because the auto drives so much better in these particular cars but yes they have 350nm of torque.I remember driving a friends auto petrol corrolla on the other hand and it was not very enjoyable,felt sluggish.I've always thought it was due to ZF making great auto boxes as the main difference compared to what Toyota uses.
So is it the box or just like you say down to amount of torque available.I won't be surprised to find that it's a bit of both