It actually is fixed. A while back in this thread I posted that if you go into settings > call settings and select the check box to always use proximity (it mentions something about horizontal orientation), it will perform as expected during calls. so no more swiping over the sensor with your thumb. That same solution has been posed in the known issues thread as well. It's a quick and dirty fix for something that, yes, out of the box, the rom does have an issue with. Good news is that it's so easy to fix.
I think this is about right. The sound is making some progress, however, since headphones and the phone's speaker by itself (during phone calls, for example) both sound alright. But when you go to external speakers, the fidelity just isn't there on the low end. Time will fix it, and I can live with that in order to have just about everything else working..