Very, very rarely do I ever create a character who is intended solely for romance,
but I would be lying if I said I didn't enjoy it when it developed naturally between two characters.
For me, the biggest favorites of mine for characters and how likable they are in a pairing is
contrast. Job, build, height, age, personality, world view: the more the better, though I rarely like full evil: I prefer shades of grey.
As for individual characters being likable, most of it comes down to execution. I greatly dislike mixed sex (futa/intersex/herm) characters, but there are a couple I absolutely adore because I was allowed to grow attached to them as "people" before the involvement of genitals.
Other traits I like... I typically like tall guys, very short girls (paired with someone significantly taller, especially), and I'm not a big fan of overly fluffy or romantic characters on either end.
I like when characters are shaky on personal space and boundaries, either they
try to be respectful but get too excited, or they're just uncaring enough that it doesn't matter to them very much.
I can only think of one pairing I RP where the characters don't have a lot of contrast, and it involves a woman named Rare and a man named Brock (owned by
@Shirelin ).
Both have spent their entire lives in servitude towards shady cloaked figures, and both have hands covered in the blood of supernatural and magical creatures. Both have submissive tendencies and enjoy little luxuries and being quiet together. They enjoy trying to make the other blush, and they are both quite tall, and both have black hair and brown eyes.
Rare differs from Brock in that she was forced into a master/slave relationship with one of the shady cloaked figures, forced to learn magic, and forced into becoming a masochist and believing her place was below men. She enjoys wearing dresses, makeup, and putting in effort to look beautiful daily.
Brock meanwhile has very strong feminist streak and follows a code not too unlike the Code of Chivalry. He keeps himself clean and shaven and trimmed, but he doesn't consistently wear fashionable or fancy clothing: instead opting for simple and serviceable. He submits to Rare willingly and acts as her protector.
On the other end of the contrast spectrum, we have K and Delaney (owned by
@Cerulean ). They are both humans and both live in a modern world where not having magic is seen as a disability with almost as much stigma as Depression in the real world.
K is short, incredibly underweight, can't match his clothing, and does not take care of himself. He's disabled in many ways: Autism, Depression, lack of magic, ADD, and likely more that haven't been diagnosed yet. He's overly clinical in his words and actions, and rarely becomes emotional. K is also agender, asexual (oblivious type), and female-bodied, prefers "scholarly" he/him pronouns, but in the end doesn't give a damn what he's called, as long as it's not "little girl". Despite his lack of care for himself, he can be freaked out by "unsanitary" things like being touched by other people. He can't make or read expressions well at all.
Delaney is tall, fat, and strong. He works out and takes care of himself. Fairly normal guy, overall. He would have been a sports star if not for the weight that refuses to go away. He's a gamer who likes FPS games almost as much as he likes girls in skimpy clothing in RPGS and dating sims, and anime. He is 'normal' in that his sex and gender are the same and he is straight. Delaney has no issues with touching others or reading expressions.
... I went off on a tangent. Fuggit. -posts anyway-
