I once had a flight on NW. After they called the elites, the card holders, FC, and all of the other special groups, there were exactly 5 of us remaining to board a completely full DC-9. (Yeah, it was a while ago.) The following suggestion may go a ways toward making that happen on some WN flights but here goes. (Ain't gonna happen anyway. But, that is what we do here: make suggestions that go over like a COS pole vaulter with WN.)

You can elect to board as a group, board after preboards and before Business Select on one and only one condition: You must take seats from back to front.

That is correct: the first group of six to step up gets the last row. They also get to sit together without any deception or anti-social activities. They do not have to worry about check in. They can all be C's and they get to sit together. It would possibly knock some time off boarding. (Hint to WN, you do want to reduce boarding time, right?)

Groups and large families get what they say they want. "We just want to sit together."

I am willing to bet they don't just want to sit together. They also want seats near the front or to get off early or whatever. They want to sit together in certain seats, a much different thing.