I like characters that are basically good - characters whose troubles come from struggling against painful or oppressive circumstances, some sort of burden or emotional wound that prevents them from fully realizing themselves, or perhaps ignorance or a single fatal flaw that they struggle to overcome.
I'm also the kind of player who really likes to help the NPCs, soothe their pain, solve their problems, help them be better people than they were before, etc. I'm drawn to woobies (omg Draco) whom I can protect and heal. On the other hand, if a relationship starts looking a lot like real-world abuse ("the bad boy keeps hurting me, but I'll be able to save him with my loooove", etc.) it sours me on the character real fast.
I like characters who play with stereotypes and tropes and subvert them in interesting ways. More than "bad boy with a heart of gold," I like "looks like a bad boy but is actually shy and harmless" or similar subversions. If a character is true to stereotype, I like it when they're self-aware and there's a thoughtful exploration of why they are the way they are.
I'd love to see transgender or gender-variant characters... but... with a giant caveat, that badly-written, ignorant, gross, exoticized, or fetishizing depictions are hugely disappointing and discouraging and, to me, worse than no inclusion at all (though others might disagree.) I hope that, before trying to write trans characters, cis authors spend time researching the facts and listening to trans people instead of just going off of popular culture.
And I hate to see a trans character whose entire characterization revolves around their gender. Trans characters should have a variety of motivations, quirks, interests, problems, just like cis characters (both within a single character and across different depictions.)
I feel similarly about depictions of mental illness and neuroatypicality. It would be awesome to see more sensitive and realistic portrayals, but if they're done badly, it makes me despair.
So... more specific ideas and character hooks that I would just love to read:
- asexual romance
- an autistic or otherwise neuroatypical character who functions perfectly well in their chosen role(s).
- the "ethical slut"; honest and considerate sex-positivity with strong, but not necessarily traditional, values. Especially if this character isn't a rogue.
- a nervous or shy character who doesn't have horribly negative self-image - it's just a natural part of their personality.
- a character who tries to help the PC with their emotional issues (as an inversion of the PC usually being the one who's an unpaid therapist to the party members)
- trans characters of all sorts!
- the option to have unrequited love for a character that the game recognizes. (In Loren, I believe Ramas remembers if you tried to flirt with him earlier. I loved that!)
Less uncommon tropes and archetypes that I also enjoy:
- androids/artificial beings learning to be human (or maybe deciding that humans are kinda terrible and deciding to be something else)
- forbidden romance (across race or social class, same-sex relationships in homophobic settings, across species!)... especially if it's sweet, healthy, and normal except for the pressure from outside.
- androgynous and/or otherwise non-gender-stereotypical cis characters
- genuinely good-natured, kind, well-meaning characters. Maybe other people find them boring, but I love them!
- noble demons and heroes from "monster races" (as mentioned by some others above.)
- deep friendship paths and non-romantic endings, if it fits the character.
- clever and snarky characters who aren't mean and/or specifically go after the pompous and powerful.
A few examples of characters that I particularly enjoyed (spoilers for Hanako Games's the Royal Trap, Dragon Age: Origins, and Elder Scrolls V: Skyrim:
I'm really looking forward to SotW, Loren 2, and your other projects (and while the fantasy RPG-y ones appeal to more to me, I have a housemate who's a dedicated fan of the dating sims.) I'm sure it will be fresh and exciting.