Ah, here we go... the definitive word on the subject from SOS.

http://www.soundonsound.com/sos/aug0...rmastering.htm

Vinyl is an unforgiving medium, and mastering for it is extremely difficult. Its dynamic range is a puny 50dB or so, even with decent vinyl, compared to the 80dB or more we enjoy with even the most basic digital media.
Bass is also troublesome. Bass waveforms have a very wide excursion and, with stereo, if the left and right channels are even slightly out of phase, the stylus can 'jump the track' as it tries in vain to follow different curves for the right and left channels. We take concepts like stereo bass for granted now, but back in the days of vinyl bass had to be mono.