Bass guitar sounded fine to me in level, playing and tone, hence no comment. :-) Although I was only using my PC speakers with subwoofer, not my hi-fi speakers.
If your guitar signal is just on the same reverb as the voice, maybe you've got problems with the mics getting too much room noise? You could maybe use a different reverb (if any's needed at all) for the guitar on its own, and route all the others to some sub-mix for the main reverb.
A thought though - if you used two mics for the guitar, are you sure they're together timing-wise?