I love CG - it's a great tool. I just don't think you should use it to replace reality; you should use it to augment and enhance. Do matte paintings, do composites, do replications, stuff like that, but you're taking something real and working with that as opposed to trying to fake it from scratch. The human brain can tell the difference.
I usually base my characters on composites of people I know. One trumpet player in SIDE MAN is really a mix of four different guys I knew growing up. Patsy , the waitress, is a mix of about three different people. I like doing it that way. I start with the characters, as opposed to plot, location, or some visual element. I write more by ear than by eye. I always work on the different sound of each character, trying to make sure each has a specific voice and speech pattern, which some writers could care less about.
I worked out a book which I thought was just straight science fiction -- with everything pretty much explained, and suddenly I got an idea which I thought was kind of neat for working in a mythological angle. I'm really struggling with myself. It would probably be a better book if I include it, but on the other hand I don't always like to keep reverting to it. I think what I'm going to do is vary my output, do some straight science fiction and some straight fantasy that doesn't involve mythology, and composites.