It depends on what you find attractive and why you want to date someone. Do you make the assessment based on physical attraction alone? I don't.
Friends and romantic interests are not necessarily mutually exclusive categories to me. You can be just friends, or you can be just romantic interests, or you can be both.
I want to marry the man who will be my best friend. Not everyone sees things that way, so I respect the differences of opinion on this.
There's a lot that goes into how I view this, including Catholic teaching on chastity, wanting to build a lasting relationship that doesn't end after the first grey hair sprouts or when the wrinkles start to multiply, wanting to enjoy time together with some common interests, being able to tolerate each other's quirks (if you're not friends with someone, the quirks quickly become annoyances), and so on.
As for the whole bad boy / nice guy thing, those generalizations do not apply for me. I have zero interest in dating any guy who is disrespectful, or who has commitment issues, behavioural problems, or addictions.