Here is what the word on the street is :-)  Hope CS can clarify.

It has something to do with a Soundblaster API that does not work for a lot of people and just never will, no matter what (short of getting a Soundblaster card, I guess).  I don't know this to be the case, just offering an explanation I heard that made sense to me.

I can say the existing fixes -- the sound / slew change in the config file and the msvcr71.dll in the Windows System (some people say in the FSX root directory, but not CS) do not solve the problem of cockpit sounds disappearing for those of us who have that problem.

Perhaps a related problem is the engine sound on all the time, which seems to be pretty common, and has always plagued me.  I wouldn't mind seeing that one taken care of somehow.

These are not show-stoppers for me, but one likes to see improvements from product to product as time goes on.  The night lighting difference Captain Sim reports is alone enough to convince me to buy the airplane.  EDIT -- yes it was.