I get what you mean, I never liked the black & white distinction between MG and SG either, but its the easiest way to explain it to people. Fact is, some girls get more attention than others. And I don't think the fact that some of your players might potentially prefer one of the "side girls" more than your "main girls", should stop you from introducing compelling characters to add some variety.
I liked the character concept of Raven, but I didn't want one of my main love interests be a stripper.
I'm really glad you like her so much, and rest easy, you will see more of her. Guaranteed