Whiny is a word I dislike to the point where someone who complains about it, sounds like they are whining. Overused in the majority of situations.
I would like my character to have a range of choices from snarky to polite to rude. And I would like the NPCs to have personalities.
I want them to be interesting and I want to like some of them, be surprised by a few and occasionally I want to be betrayed by them, with the option of killing them.
I've always found BioWare characters satisfy this regard. Whether I like them or not they have been interesting. Jack, Thane, Sky, Sam, Steve, Garrus, Mordin, Wrex, Morrigan, Alistair, Wynne, Zev, Leliana, Cullen, Nathaniel, Ashley, Tali, Wrex, Cole, Solas, Cass, Dorian, Blackwall, Sara, Kasumi, James, Joker, Edi, HK47, Jolee, Canderous, Master Li, Ashley and even Maranda. All of them have entertained me. Even when I didn't like their personality, Morrigan, Zaeed, Maranda, Oghren, they still entertained me.
I Loved Carth. He had some of the best dialogue ever and I will never ever get tired of "I think you hurt my man feelings", and "I'm all ears Beautiful". And same goes for Kaidan. I adore that character "I'll try to keep the deck dry"; "I'm 32 Shepard, you don't serve as long as I have without coming to terms with yourself"; I do hope they have one or two that have the boy scout image and I also hope BioWare makes characters who stand for what they believe and don't jump in line just because my character says jump.
I don't have to like them all, I don't think I'd enjoy a game where I liked them all 100%. A good character can be someone I dislike, if they make me feel something it's a good character, but for the most part I would also like to have the option of picking the ones I want for my team and leaving the others behind, like Garrus and Wrex, or most of the ME2 group. I'm sure there will some we have to include, there always are but the one thing I have never had a major problem with, are their characters.