It's never been the models or the graphics, for me, it's always been everything else. The animation, the sound design, the atmosphere, the positions/variety, and the mechanics.
The graphics are just the presentation. If you get caught up on that, you're missing the forest for the trees.
Granted, I hate the dime-a-dozen 3D garbage that's been pumped out factory-style late, but what separates succubus heaven from it all, is animation.
Anyone can pose an uncanny 3D model and type some half-engrish text to describe what it's doing and how that's supposed to make you feel, but it takes actual effort to make an "action" game,
or as we used to call them in the glory days, an RoR.