Some of the characters in the series look gorgeous. The texture and design work on Thane or the Turians looks awesome (though the Turians need higher rez textures). General "walking around" NPCs have always looked pretty bad, but I always chalk it up to them looking like real people: like in real life, for every beautiful person you see walk past you, there are going to be 10 average, bland or ugly people.
Some humans look awesome though. Traynor looks and sounds exactly like Parminder Nagra, so much so that I thought they did the same thing as with Miranda, Allers, andand scanned her face and used her voice (color me surprised that she's not Parminder). Jack's face, as I've said before, is a beautiful blend of Angelina and Natalie.EDI
I think what I don't like about the character designs is something that's been apparent in lots of games with heavy detail - seeing all the moles and blemishes and dimples on the characters, it's just a bit too much detail for me personally - I prefer stylized looking characters mainly - The Witcher games were like some of the only western RPGs which I felt had attractive characters for some reason (possibly due to general attractiveness of Polish women?). I also think that the skin looks very weird in certain lighting conditions in ME3.