Forget "women's NHL". Go straight to the mixed team format with minimum 2 persons per sex per line-on-ice, while the team quota would be minimum 40% of either sex, including coaching staff.
People of different sexes reproduce and spread humanity here together, why not some quality hockey too. That way we could have a decent, culturally, socially, genetically, and environmentally adapted breed of hockey players sometime around NHL's 500th anniversary, due drastically increased likelihood of reproductive marriages between top level hockey parents and centuries long selective interbreeding/pedigree. Note that in this concept, to ensure enough wide genepool and healthy generations of future hockey players, we must use maximal available variety of human genes, thus maximal utilization of global human genepool is must when introducing new studs and dames to the game. Maximal genetic admixture ensure best results even after 500 years of NHL. After all its a question and the project of milleniums.
Future tech will ensure also use of good genes of the best of past hockey player generations, by careful opening of graves, dutifully taken DNA-samples, and cloning. A clone series of same age player would then train as a junior units against other clone series of other legendary players to determine who are better. Also, individuals of same clone series would put under intense infight situations with slight variations in their coaching methods to determine best training regime applied to same genetical clones...
:p