Muslims For Progressive Values

I came across a group called Muslims for Progressive Values and learned that they are contemplating creating their own madhab. While I may agree with them on some issues, and respect them as Muslims, I have some serious points to bring up about the idea of creating your own madhab, apparently just to be more liberal and accepting of homosexuality. Forming a new madhab, I believe, will just serve to create further division in the Ummah. The pressing need of the hour is solidarity among Muslims, not further division. Muslims are threatened on all sides; we do not need to be enemies of each other as well. Instead of setting sail from the mainland in a newly constructed canoe, I would suggest pouring more effort into repairing the existing cruise liners. There were times in the past that the Muslim community was much more liberal; even today, most Muslims are far more liberal than they would care to admit. There were times when the Muslim Caliphate did not punish homosexuality, and the other human rights you seem to believe have never existed before in the Muslim world were commonplace.
Nevertheless, if you are going to persist in this, there are some serious issues you must consider: How will you derive law? What method do you propose for creating a judicial structure? It is necessary for a madhab to have a method of deriving law; what will yours be?
And once you have your method, please consider the following issues:
Evolution: What is your stand on the origin of the universe and its age? How did humans come to be?
Mental Illness: What, in your opinion, are the causes of mental illness? Which illnesses exempt you from criminal accountability? How should mental illness be treated/cured? When is an individual considered cured? What is the status of an individual who commits suicide while suffering from a severe mental illness (such as depression or bipolar disorder)?
Prayer Method: You believe women can lead men in prayer; yet what about when a woman is menstruating? Is she required to pray or not? What is the correct way to pray (position of hands, etc)? How do you even decide this?
Rights of Men/Women towards each other: What are the standards of modesty required? What are the responsibilities of family members towards each other? What constitutes a family?
Divorce: Who can initiate a divorce? What is the necessary method? When is the couple considered divorced?
Marriage without a Wali: If you accept gay marriage, many parents will refuse to give their children in marriage even if it is acceptable in your madhab. Do you permit individuals to marry without a wali? Who is even required to have a wali?
Adoption/Surrogacy/IVF/Sperm Donation: When are you considered the parent of a child? What are your responsibilities towards your children? What are your children's responsibilities towards you?

These are just some of the issues I can think of off the top of my head. I may add more.