Though I am happy for same-sex gamers to at last have more options then Liara or the Consort in ME, I am somewhat concerned that said same-sex gamers, and even straight gamers, might jump to the conclusion that many of the previously introduced or core characters will suddenly become Bi-Sexual when there was never any indication that they were. Frankly, due to a higher quality level of writers over Dragon Age and greater level of expectation, BioWare is without a doubt going to avoid making the same mistakes it made with Origin's sequel. In other words, Kaiden suddenly being down for Man on Man action is highly unlikely.
Tali is also a popular option, but frankly, with all due respect, the same sex community was always grasping at straws. Tali's dialogue to a F!Shepard was more familial then romantic; to Tali, F!Shepard was like a heroic big sister. Yes, there was the cut/file hidden dialogue, but the fact that said dialogue was never used in-game none the less establishes the orientation of the character. The argument of the linking suits is defeated by the fact that Tali's aunt, as well as other Quarians, link suits as not *just* a sign of intimacy in the romantic sense, but as a sign of close friendship, family love, and trust. Tali even confirms that in dialogue with both sexes, though with a M!Shepard she obviously goes a bit further.
Given that Casey mentioned that the game would be trying to avoid new Romances, I think it's quite likely that the same sex LIs will be a mix of the two new characters (possibly) and non-squadmate NPCs. An example of the later being the Consort, Investigator Parasini, Shiala, etc. Given that Mass Effect 3 is meant to be the culmination of a highly immersive, somewhat serious, action adventure epic, suddenly making non-same sex characters Bi-Sexual would break said immersion and reduce the narrative of character development to an almost cliche, tongue and cheek status.
That said, these are just my opinions and observations. If said views turn out to be incorrect I will still feel quite happy for same sex gamers and will still enjoy ME3 in a big way. I just don't want to see folks getting their hopes up simply because of the concessions made in DA2 which were, frankly, poorly implemented.