I had a very different experience around 20 December. The line was very long. They allowed first class/elites to the "front of the line" where the ID/boarding pass screeners were. They then broke it up into three even lines, and there was about a 30 minute wait from there, but it did save me about 20 minutes or so. And, this was for the 0730 DTW flight. So, I would say be there very early as NWA has about 3 or 4 flights prior to 0730, and ATA, Midwest, and Airtran (I believe) also have flights leaving in the early morning.

By the way, the man behind me in line originally missed his flight, I believe.