Asking for Alistair and Morrigan to be open to both genders is exactly the sort of thing that every frothing forum member with their pants in a twist conjures up as their feared endpoint of Bioware introducing more LGBT characters - why would you give them that ammunition? What's the point? Is this the figurative battlefield you want to die on?
Not only is it making a quixotic stand against something that happened two games ago, now, but by retroactively asking for something that the developers never intended, you're basically wanting official acknowledgement of modded content. Every single terrified "omg what if Alistair hits on me, we were bros" objection suddenly becomes more or less valid - and for what? Does the injustice of not having equal options necessitate demanding that Bioware change their original vision?
I think the ME case is not a good comparison at all - before ME3 there were zero male same-sex romance options in that entire series, period. There were zero gay characters, except for one side-character in the book series who was retconned as straight and killed. The Kaidan romance was, if anything, a half-hearted way to give male Shepards a second romance option (over three games, mind) that needed only a few line changes from femShep's. If anything the more appropriate example is DA2, where the team introduced equal numbers of LIs for all genders and orientations.