I’m just reviewing and tweaking some Songs and I’m just blown away by how lame the Voice sounds when I compare them to the same patch in Voice mode.  Is this really just a matter of resetting the Parameter w Voice switch? And should I be doing that with every single voice in the Mix, even the sequenced/recorded ones?

Parameter with Voice and applied effects are reasons why a Voice can sound different when used in a Part.

Your member profile and previous posts seem to indicate that you have a MOX and/or MOXF. However, you’ve posted in the XS forum - this support article would apply to that model:
http://www.motifator.com/index.php/support/view/copying_voice_data_to_a_performance_or_mixing_program

If you have an XS, please edit your profile. If not, the specifics of the article won’t apply, although the basics will.