Women prophetesses have biblical antecedents: Miriam, Deborah, Hulda, Phillip's four daughters.  Women elders have no biblical precedent.   

You are conflating two very different issues when you compare uncircumcision and women's ordination.  Paul said circumcision and uncircumcision are, 'nothing'.  He vigorously opposed circumcision for Titus and he circumcised Timothy with his own hand.  He obviously believed the covenant with the Jews remained.  He didn't want gentiles to get circumcised; just Jews.  There is nothing in the NT to suggest Jews are not required to be circumcised today.  Times have changed but the covenant has not.

I'm surprisingly flexible when it comes to what I think women can do in church and for the church.  What I oppose is a hermeneutic that teaches the church has the flexibility and authority to countermand scripture. 

Too often we don't even get to the bible.  The doctrine of equality is all the authority   WO proponents think they need.