Terry,
the sound now is no doubt cleaner; I think they improved a lot the DSP algorhytms, because the reverb now is much better. Maybe that's the reason why the acoustic piano now sounds so good. Other instruments -like the electric pianos and the guitars- have been totally resampled and now are more or less like the XD9/XD3. However, I have to say that a few sounds -like the Golden Trumpet or the Pop/Rock Tenor- have lost that "dirty" quality which made them so real.
Anyway, I guess that you are right and I'll have to record something...an example is always better than a thousand words...
:-)