Althought I am just learning AVID and I have never exported from AVID to WMV, my experience with other editing programs such as Premier and Final cut is that compressing to WMV will be always better with WMV own encoder, wich you can download at https://www.microsoft.com/windows/windowsmedia/download/default.asp.
Then, another thing -and this is just as I see it and probably has no technical backroung or explanation- When exporting to WMV I go first from DV to MPEG1 with very high bitrates and with the gamma value a 15-20% under (wich means, the video go down this percentage of light in each pixel, making the black more darker and making it look better in computer’s screen).
Going from DV to MPEG1 got to be done witha good compressor. I persoanlly go from Premier to MMPEG1 with Raptor RT software/hardware, but AVID has probably a good encoder too.
ANyway, very important when compressing to WMV:
Deinterlace ; lower gamma value; and keep an eye in the bit rate of the final video.