Though I think the OP's points are well stated, and many other fine examples have been made over the course of the thread, I think this time around BioWare will likely try something new, or at least a "mix" of concepts, with the story's respective Love Interests. If you look at every BioWare title that has included LIs as options, each consecutive title has tried something new or played with the preconcieved concepts a bit. If you look at how Romances where handled between the Baldur's Gate series and Neverwinter Nights, there is a significant difference.
In BG I-II the romances played out over the course of the series and were in-depth enough that one could even impregnate thier respective love (I don't know if it worked in reverse, I never played BG has a Fem Hero) over the course of the series. Also, the Romances where as varied as thier endings; i.e. Aerie (my favortie) was the "Super Mega Happy Ending" followed by Jaheira who was the "Bitter Sweet Ending," and lastly by Viconia who was the "Romatic/Tragic Ending."
In Neverwinters Nights the Romances where more subdued and seemed to have been set up so that they never really became as impactful as the story, though it was a step closer to the concepts that would become more of a staple in BioWare Stories. Linu was a perfect example of the Sweet/Awkward LI, while Sharwyn was the Sexy/Spicy LI. Though those romances never amounted to much aside from a bit of "Let's see what happens when this is all over," dialogue from Linu and a Kiss from Sharwyn, I think they really set the tone for the kind of Romantic concepts that would come later.
Next came Kotor, and the Singular Romances for the Male or Fem Revan. Both Characters encompassed *all* the attributes of LIs from previous BioWare titles in one package. Both Bastila and Carth could be Sweet, Spicy, Sexy, Brooding, and Cold depending on where the PC was in the relationship with them. Though rumor had it that BioWare wanted to include more Romances for the PC (Mission for Males -a slightly older Mission-, Juhani for Females) the idea was scraped by LucasArts in favour of keeping the Romances more "Star Wars." And it worked to some degree. At the game's climax when you had to choose between either the Galaxy, Your Romance, or Having Both the emotional impact was effective.
Next, we had the LIs of Mass Effect, which took a page from Kotor in that all three (though envisioned originally as *four*) LIs encompassed various personality traits and concepts. Liara, Ashley, and Kaiden could be Sweet, Sexy, or Cold depending on how your Character Pursued them. Though Liara was the more gentle/awkward out of the trio, BioWare attempted a kind of emotional Balance game between them. With ME2 the Romances took a similar route, but were given extra layers of complexity or depth. I think the most interesting Romance (aside from the fact that Tali was my favorite) was Samara's romance; basically, all the pieces where there, including mutual love and attraction, but something "more important" had to come first. It was a unique and slightly jarring outcome, and I think it showed that BioWare and it's brilliant writers have no desire to stick with the same formula again and again. They want to experiment, mix things up.
Since DAO has been covered in depth, I won't go into details, suffice to say with Dragon Age 2 I would not be surprised to see a mix of what we had in ME2 instituted in the DA sequel. We know Isabela is promiscuous and open minded in her views of "Romance" but we don't really know all the details, so it might be too soon to drop her in the "Spicy" catagory. There might be much more too her then that. As for the supposed "Sweet" LI, well, I have my Heart set on Aveline, though much like Isabela we don't have alot of details, less even. She has not even been confirmed as a LI. Even if she is, given her background as a Templar's Wife (possibly not a happy marriage) there could be far more to her character then simply being DA2's Leliana.
To sum up, BioWare loves to mix it up when they can, so any preconcieved notions of Romance Templates should be kept on the back-burner until we can sit down and see how things play out. At this point, all we're likely to do is get ourselves all excited for Romances that *might* not play out as we think they will. Still, looking forward to it.