Being one of the schools of Mahayana (I'm a 20-plus year student of the atiyoga of that), I'd think that coming under the auspices of the Dalai Lama, this move, especially if followed by other temples, might work towards not quite forcing his hand in policy (though I'd love for him to make amends before he passes--we so deserve this) but maybe at least prompting some voice in commentary.
If I understand correctly, his most currently expressed view is essentially that being gay is perfectly fine for non-Buddhist. So that both contradicts the science of us and it applies to us doctrine never uttered by the Buddha nor expressed in the earliest Buddhist texts. So that's just heterosexual hegemonic crap he's laid on us to appease his homophobic masses and he needs to fix that, to fix them, so we can continue better to fix us.
Sanctifying religiously a same sex relationship flies in the face of the Dalai Lama's expressed and espoused misinterpretation of applying the Buddhist precept of sexual misconduct to being gay.
We look forward to his brave and clear response.