Here are some features of Christianity that I believe have staying power, despite strong streams to the contrary at present.
1. A genuine love
Forms of Christianity right now that focus on what you believe focus on the most superficial part of the human brain. Our motives are deep, and our choices are what define us. What arguably matters most to God is our "heart," our intentions toward others as they lead to our choices and our actions. This focus is real. This focus is genuine. This focus shows up in life. This focus will persist.
2. Interest in the whole person
You cannot neatly divide up a person into mental, physical, and spiritual. A person's eternal trajectory may be the most important aspect of his or her life, but God is genuinely interested in the whole person. For those who are "burned over ground," the frontal assault to try to convert is counterproductive. Christianity that will persist will need to build relationships, be genuinely interested in the whole person (meaning physical, social, economic, and needs of all kinds), and let issues of spiritual trajectory arise in God's own time. This principle carries over to being interested in God's world as well.
3. Focus on trajectory, not event
Christianity that will persist will be less interested in mile markers than in the direction a person is traveling. This includes the person who has made a confession of faith--God does not weigh a person by where he or she has been but by where they are going. It can become a myopic preoccupation.
3. Focus on reconciliation over justice
The picture of justice as God's dominant characteristic pictures an immature God. Because love is God's ultimate character, God's sovereignty does not point to his right to condemn anyone he wants for whatever reason but to his right to forgive anyone he wants for whatever reason. Justice in the modern sense is a good, but one might argue that even true justice aims at reconciliation and protection.
4. Views all people as full participants
Artificial distinctions between men and women, between races and social groups are at best distractions, at worse fallenness trying to disguise itself as godliness. The roles we play should ideally come from the gifts God has given us. Christianity that will persist will be color and gender blind.
5. Scripture as our story
Fundamentalism is strong because it plays to simple understanding and simple answers, not to mention frequently base emotions. It creates an idol of words and mistakes words for the Word, Jesus Christ. In Scripture Christians find their story. They find God walking with his people in the past. Christianity that will persist will live in full recognition that we must "work out our salvation with fear and trembling" as we make our way through life, recognizing the constancy of God from the past--revealed especially in Christ--but also his principle of meeting us in flesh, of incarnating truth and ethics in specific contexts.