"Missional"? What?

Today I learned about the North American Mission Board's new Missional Network, and it made me wonder what actually makes a person or a church "missional". I've been hearing and reading that word a lot lately, but nobody seems to ever say what it actually means. After going on a small quest around the spectacular world of cyberspace, I stumbled upon perhaps the best explanation anywhere of being "missional", which was written by Tim Keller. Based mostly on his explanation of the missional movement and also on some personal observations about it, here are what I think are its positive and negative aspects:

The Good:
-It helps alert Christians in America that we are no longer living in a Christian society. America is following Europe's lead in relegating Christianity to the annals of history. In a society that is increasingly post-Christian, we can no longer act as though it were Christian. We must approach our culture with understandable language and without presuppositions of what they ought to know about Christ.
-It shows us that we have to get to know our culture and not assume that everyone is just like us.
-It emphasizes (in theory) becoming counter-cultural. Whereas in the past Christianity was a part of our collective identity as Americans, we now see a need for living in a way that distinguishes us radically from the culture around us.
-There is a strong emphasis on social justice, which has been severely neglected in Evangelicalism. It shows us that standing up for the weak, the poor, and the oppressed does not mean that we have to embrace liberal theology.
-It seeks to establish churches that are not defined as "white", "black", "hispanic", etc. Just as Paul taught so clearly that divisions between Christian Jews and Christian Gentiles were sinful, the missional movement teaches the same about the racial divisions of today's Church.

The Not-So-Good:
-There is a destructive confusion between humility and self-deprecation. At times it is difficult to see whether the missional movement stands for anything at all because it is so focused on tearing down stereotypes and criticizing the mistakes of Christianity's past. It is hard to tell what a missional church is, but it is easy to tell what it doesn't want to be--traditional. All this is done in the name of humility, but is it really humility if you are criticizing a stereotype rather than yourself? And even if you do criticize yourself, is that the same thing as humility? No, it's not. Humility is submission of our own will to God's, not open proclamation of our failures to do so.
-There is also a dangerous emphasis on tolerance. How can we be thoroughly tolerant and radically counter-cultural simultaneously? Perhaps the answer is that the missional movement does not actually want to be as counter-cultural as it says it does.
-There is so much emphasis on familiarity with the culture that it risks leading Christians to "love the world" in the way 1 John 2:15-17 warns us against. I agree that we must know what our society is watching, reading, listening to, etc., but we are not to embrace those things. In this respect the missional movement walks a very thin line between what it calls "cultural relevance" and sin.
-There seems to be a fear of rejection and persecution, both of which the New Testament encourages us to embrace as we stand for the truth. This fear could potentially compromise the saving message of the Gospel.
-There is an overemphasis on unity across denominations. Even the heretic John Shelby Spong has said, "Unity is a virtue in the church, but not the supreme one. Truth is higher." If the pastor of the United Church of Christ down the street doesn't believe in the virgin birth, our job is to preach the Gospel to him and not to partner with him.
-There is a de-emphasis of Christian doctrine for the sake of emphasizing methodology. As history has shown, that leaves churches wide open for heretical teachings to creep in.
-The word "missional" itself is too easily confused with "missions". Being missional and doing missions are not the same thing, but if someone criticizes the missional movement they can be painted as "anti-missions". A new name is in order. Any suggestions?