I don't recall anybody complaining about the volume level in the X. Probably someone has, I just haven't seen it.
The D2 and X are pretty similar, a few differences here and there. I have a D2 and volume is not an issue.
Just to clarify, are you talking about phone volume or notifications? Also just to let you know there is a Gingerbread leaked version you can install but I don't think it did anything with the volume. On my phone as a matter of fact I could barely hear on my first call. A reset however fixed that right away.
when the droid x came out, half the people who had it were complaining about the volume issue. then moto released an update that fixed it.
when i got a droid 2, i was really upset about my volume being too low as well. the og droid had an insane volume level when playing music, idk why they downgraded this feature. it really gets me angry since im an audiophile and all. this still hasnt been fixed on the d2 since no one cares about it