The answer has been staring the all male celibate hierarchy in the face for decades - allow men and women to be priests and end mandatory celibacy.  

But more than that, it is necessary, I think, to end the idea that some "ontological change" creates the ability of priests to create and deliver the sacraments.  We can have Eucharistic celebrations, baptism, confession, marriages, anointing of the sick without priests - all that is really required is faith in Jesus in those who gather in His name.  This idea that a priests stands in "persona christi" has to go.   

It is also important to bring lay people into governance of parishes, dioceses, and the Vatican.  Patriarchal/monarchical hegemony has been dying around the world since the Enlightenment.  It has only been in the last 100 years or so that masculine hegemony has started to crumble.  Time for these changes to be recognized in religious institutions as they are recognized and practiced in other areas of our lives.