I agree with Lycia. I think it comes down to having integrity. If you have that, and all the things it is comprised of (being trustworthy, honesty, genuine, virtuous in your intentions behind your actions, etc) then you will make a good sub, regardless of location. Communication is also key, in general, but especially as in specific to a LDR of any sort. Communication is one of the only things you have between your Domme and yourself, as you cannot be there in the flesh to experience some emotions that can only be captured face to face.
As for the traits being born into a person, I don't believe people are born with particular personality characteristics...there is nothing innate about being a good person or an asshole. It's about the nurturning of that person, so YES, it can be taught if that person is willing to learn. But that falls upon the burden of the sub to be willing to receive such teachings/mentorings from his Domme.