I'd like to
romance a really quirky, maybe a bit simple character, not necessarily traditionally attractive character. Someone like Wrex or Grunt(except y know an adult) would be nice, but I think to others it would just be a joke
Something like having an alien character with low social skills doing something extremely cliched like giving you flowers to show their interest because the extra net said humans like flowers. Or giving you a still beating heart of your enemy.
So alien
romance for the win! It would nice if there was a weird cute gaylien
romance, but I would be happy with gaylien more traditional
romance too and weird cute straight
romance too

but somehow I doubt any of this will happen...
It could be nice to have an alien that is straight/gay with their own species, but bi/pan with humans. It could be a chance to explore thebtopic a bit. But in the end if a person has preferences to either female or male characterics as they are viewed in human culture I quess it is logical that they would find those same qualities attractive in a partner regardless of species.
It would also be interesting to explore a society where reproduction has nothing to do with relationships. Best genes would be selected from individuals and babies made. When you want to start a family with your spouse you would "adopt" a baby.