I am not sure what I think of this - I think he is coming from an acceptance of gay marriage, which is great in an of itself, but there are so many attempts to erase sex at the moment I instinctively don't like this however well meant. I would rather a pro-gay-marriage bishop sought a new marriage service, write in conjunction with gay and lesbian Christians, and then commissioned a literary figure to write their ideas into something beautiful that could be really valued for generations.
All a bit before hand as the CofE have not got any where near accepting gay marriage yet.
archbishopcranmer.com/bishop-of-liverpool-gender-neutral-male-and-female-marriage/