You have to consider that SE is trying to protect the interests of both parties all the time. They allowed Eternal Bond to have same-sex unions, yes, to make homosexual couples happy, but they also changed the ceremony's name (remember Yoshida's frantic "Don't call it marriage!" in the interview?) to not offend the sensibility of those against same-gender couples. They also gave the ceremony several ways to seal the two participants (a toast, signing a document, a kiss) to give space to other kinds of boundaries between the couple. So that, to you, they can say "Yes, same-gender couples can be together!", and to those against same-gender marriage, they can say "Oh it's not a marriage. It's a pact of undying loyalty to each other. They don't even have to kiss! Even best friends can do this!".

It's a very delicate topic that can cause great turmoil in the community (and the parents of some of the younger members of the community) is one platter of the libra gets too heavy. So I personally wouldn't expect them to put any obvious hint of same-gender relationships in the game. They may put characters with obvious tendencies/behaviors (Thinking of Alexiei Mayakov in FFXI), but I doubt they'd give them partners or display them into romantic affairs. They're selling a product, and in doing so they need to please the vast majority of the potential playerbase. And the majority leans on the etherosexual side, so they will follow that approach over another.

As for Valentine being depressing to single.. as a single person, I can understand. But that's only because of how you force yourself to look at the festivity. I was raised and being taught that St. Valentine is the celebration of love, any kind of love, and until we had to separated, I mostly celebrated it with my mother (she is devorced and I'm an ever-single girl), because I loved her and she loved me. Sexual intercourse has nothing to do with St. Valentine. You can celebrate your love for a relative, a pet, or even one of your idols. To claim that it is a day just for couples is, to me, a great display of arrogance, because not everyone can have a partner, but everyone can have someone they love someway. And arrogant people shouldn't deserve a special day for themselves.