@Who Knows: Dragons and magic are just some of things that you would naturally associate with a fantasy universe (which Dragon Age is), so therefore it's not surprising to see them included, thus it would be silly to complain about them being unrealistic (also, as they don't exist in the real world, we have nothing to compare them to) - if someone was to actually complain about dragons and/or magic being included in a fantasy universe because they're unrealistic, then they're stupid.
Having all four of the romance options in DA2 (the ones included in the game proper to begin with) be bisexual was most definitely pandering and quite unrealistic for my tastes (really, not even one straight character among them?). If it was like in the first game, where two of them were bisexual and the other two were straight, I could probably have believed that - but all four of them bisexual? Yeah, I'm calling BS on that.
I'm calling BS on the fact that there can't be four bisexual companions without it being pandering.
Here's the quantitative data on love interest sexuality:
DA: O - 50% straight, 50% bisexual
DA 2 - 80% bisexual, 20% straight
DA: I - 50% straight, 25% bisexual, 25% gay
So, if you look at the data from a whole (all 17 love interests), you have - 47% bisexual, 41% straight, and 12% gay. So, there's nothing saying that there should be more straight LI's than bisexual ones. You are using Earth statistics on Thedosian sexuality. Not applicable.
That being said, a group of four people are hardly representational of the population at large. No one expects them to be, so using that criteria is pointless. It's not uncommon for four bisexual people on Earth to be in a group of friends. Why would it be on Thedas, where there are clearly many bisexual people?
Finally, maybe the Bioware writers just wanted to tell the stories of four bisexual characters. I love how it's pandering if there are four bisexual characters and the advice is "Bioware should just tell the stories that they want to tell." But those same people refuse to entertain the idea that maybe those are those stories. They just aren't the stories you want Bioware to want to tell.
And, of course, all of this being said, I don't see how it relates to the concept of a gay knight in shining armor character to begin with.