For me there is nothing worse than not being able to romance a character I've fallen in love with. Mind you, I mean "fall in love with" in terms of a writer/reader type love, not that I've literally fallen in love with a non-real person lol But I always wanted to romance Alistair for example and he was cut off from my character; by the time I decided to play a female Warden I was tired of DA:O and couldn't get through it (I did get her rose for her though

). However, luckily Alistair is such an integral part of that game that my Warden being his BFF was almost as good as being his lover; I still got to intimately explore that character (though romance would be better).
And now I'm playing ME and feeling sad I can't romance Joker. Not because I want to see him being all naughty with my character (don't care about that stuff, believe it or not

) but because I find his character fascinating, and I want to see more of him, the more intimate (as in emotionally intimate) side of that character the way you only glimpse in a romance.
And of course I just like romance stories, even more when they involve my favorite characters. I mean it's like all my love for GOT is kind of slowly ebbing now that Arya and Gendry have been separated, and it's obvious to me that Gendry's going to die and I'm distraught that my OTP has been forever severed lol
So if we can't romance Cullen, but he is just a companion... I will be sad. Similar to how I felt about Sten. I love that character... but never got to see who he really was, just the face he put on for my Warden. I would hate to only see that outer shell of Cullen as a companion... it would be like Aveline all over again.