That's exactly what this does. Unmarried couples, either gay or straight, can now specify in writing who can visit them in the hospital. There's nothing about this that says hospitals have to allow visitation rights to someone just claiming to be someone's partner.
That’s not my point. From what I read it goes to also giving gay partners medical POA. Currently, you can give anyone medical POA in writing. This seems to indicate that gay partners now have that right without writing. Next of kin can make medical decisions for an incapacitated person based upon legally recognized relationships. There are legal documents which are evidence of such relationships (marriage licenses, birth certificates). Without such, how does a hospital shield itself from liability if someone claims to be a “partner” but it turns out the incapacitated party does not have the same intent?
This is not an issue of visitation, but of medical decisions. I just think the hospital can be caught in a no-win situation in some cases where the parties may not view their relationship in the same light, but one is incapacitated and cannot speak for his own medical decisions.