RH X5.0.2 didn't do any better with lists when importing Word
files, either. My guess is, that the fault lies equally between RH
and the third-party product whose files are being imported. That
is, any number of authors may have used any number of unorthodox
formatting gymnastics to achieve bulleted and numbered lists, and
RH concerns itself with only the approved, default methods.
We found that performing much of our cleanup in the Word
files prior to importing, went a long way towards making our
transition smoother (target output was a 42-project merged WebHelp
output of ~2400 topics).
Perhaps some FrameMaker users can add more detailed
suggestions.
Good luck,
Leon