Before nudity really makes sense, I would want the game engine to be updated so that character profiles are b-spline rather than polygons. People should have rounded profiles, not pointy edges.
And to make *that* work, you would have to drastically alter the rendering pipeline and possibly the storage format of the art assets. (I think you need to push the rendering of that geometry into the pixel shaders, leaving the vertex shaders to just render a "frame" which holds the character's image.)
And that kind of radical change? It comes with a fair amount of technological debt and business risk (though possibly also with improved visuals or improved rendering performance or similar payouts). So I would not expect to see it any time soon. This use of shaders might also reduce their availability to produce other kinds of effects (which, of course, would be used by some people to complain about how incompetent the designers are), and possibly also limit the use of low-end hardware.
For example... if the engine rendered characters like I described you could mostly rely on depth mapping to deal with overlapping models (like weapons), but the actual "frame" that you would be looking "through" (to hold those depth mapped pixels) would probably need to be nearer to the "camera" than the character itself. And that might introduce problems when the character is really close to the camera (like you sometimes get in kill-cam shots).
And, of course, if you also are adding nudity, I expect that you would have to put up with an audience which contains people who hate whatever you do (but you always get that, anyways).
Besides, nudity is one of the first thing the modding community adds, so it's not like anyone is really missing out. Well, other than the clunkiness of how that looks in or current low-poly environment. And maybe some nudity-related character development?