We've actually been paying attention to that. To the extent that Herra made a drool worthy effect for Flak guns, and I have manipulated several effects sounds myself.
However, the engine keeps truncating the sounds (or warping them or anything but playing them to achieve the intended result), even when it is set to the same data rate as an original retail file. We've been hashing this out for a while now and yeah, it is probably going to involve changes in the engine code to do properly.
I do agree though that more than just 16bit 11khz and 8bit 22khz needs to be present. In fact, it seems almost backwards, I'd do 16bit 22khz. And lets not also forget that they are all mono channel wav files.
But now we are verging towards some murky waters. Namely, how far do we go with replacing stuff? Because at some point, we may very well replace everything to such an extent that the original game won't be required any more. How is that going to be handled by the IP Holders? Or will that day be significantly enough in to the future that it will no longer be a concern? (Okay, possibly being able to adequately Voice Act the campaigns might be a little far fetched right now, but the point is still the same, if we get started, where do we stop?)
As much as you complain about the sound (and rightfully so), I complain about the interface. Too much duplicated images and wasted space for something that could be much more elegant.