|My Audi S4 has the dual-clutch DSG and it is all the things you describe above -- in sport mode. It shifts faster than I could ever do manually so boost stays where it needs to. It does lug a bit in traffic or low speed acceleration situations when in regular mode so I just keep it in sport most of the time :-)
I'm glad that there are still people thinking about how to do things better on this platform. I would consider doing something like this if the cost were just a bit more reasonable and/or I already had a standalone ECU.