Many would probably agree that in the mind of God every human being is called into unity and fellowship under the auspices of the redemptive work of Christ. In other words, everyone regardless of race, creed, history, or cultural background is, at least potentially, a part of the family of God through the working of God's grace. If all was in accordance with God's will, then the issues that separate mankind into the various competing groups would dissolve into a perfect unity prompted by the message and mission of Christ.
This unity would not logically eliminate the many variations in humankind listed above. Different languages, various races, and multiple cultural environments would still exist, but unity would be achieved based on, not homogeneity, but on the principle of unconditional love. The search for unity in the past has been largely unsuccessful, precisely because it was thought that unity demanded perfect uniformity of thought and action. Such has never been achieved because it is inherently unachievable.
God is the author of the variety innate in humanity, so His unity is logically achieved without the conformity which has been so vainly sought by the religious world. Unity under this principle does not require that we determine whose language or political systems or economic institutions are best because such judgments are not a necessary part of that unity. Mutual respect and commitment to the principle at the heart of Christ's message are the only requirements for bringing all people together in the one family fellowship envisioned so eloquently by Christ in John Chapter 17.