As much as they are a bunch of lily livered moral cowards who will undoubtedly rue this day as a shameful moment when they failed to grasp the moral high ground and sided with the wrong side, at least they are discussing it.
Don't forget that many other christian churches - catholic, orthodox, many of the evangelical churches aren't even prepared to have the debate, so mired in immoral dogma that they can't even recognise a moral wrong if it slapped them around the face.
PD, most denominations have been having debates on this issue for almost as long as I've been alive; certainly long before it became a hot topic within society as a whole. For some it went hand-in-hand with debates about cohabitation; for others it has been a stand-alone issue.
Following the government's decision to redefine the meaning of the word marriage, every denomination has had to debate the issue. Each has been required to come to a decision as to their position in regards to the new legislation and whether or not they would hold gay weddings. In some cases, where the denomination isn't run by a central board, as is the case with Anglicanism, Roman Catholicism and Methodism, each congregation has been asked to debate it themselves. I suspect that not every single congregation did, but many such congregations I know of, did.
I'm not sure that the church will ever rue grasping the moral high ground and standing strong on this particular issue.