K6 is the top rank you can get to start Version 0.3, a dom player would really be aiming to get higher and higher ranked over time. A sub a little more extreme would want to be lower and lower, and a softer sub would probably want to try and stay a little near the middle and steer towards specific characters as well.
Oh, I would add for subs that focusing more on relationships with specific women matter more than pure sub points sometimes. For example, Dominique will probably never be an extreme dominant physically in terms of like pain related domination no matter what you do, but if you don't please her, you might miss her content, that kind of thing. Juliette would never be a soft dom at the other end, but some other characters in between are more pliable and might have variation on this depending on main character's choices. The same is true for doms in a different way -- some characters can't get as submissive and/or good/evil as others as they are more "set in their ways" but others are able to be influenced and changed from their first inclinations.