I don't have the legal knowledge to give much of an opinion, except my gut instinct doesn't agree. I think marriage in its traditional form is GOOD for society as a whole, and therefore, the law should encourage and support it. Anytime you start messing with something, trying to change it, you will inevitably get UNINTENDED CONSEQUENCES, some harmless, some not.
I don't want to go the route of Europe or more specifically Sweden, where the marriage rate is declining.
If only our society could focus its efforts on encouraging things like morality, fidelity, honor, commitment, selflessness and just good, clean living. Rather than trying to tailor everything to the convenience and whims of individuals.