Every time you post in a thread like these I start to wonder if I should have your name, because you say a lot of things that are completely incorrect or based solely on offline rendering that does not apply to real time visuals. I'm not even a veteran, but you're wrong so often that I think that name is false advertising
The model looks pretty much the same, though I don't doubt the geometry does change on the character all the time. Same model, but silhouette tessellation seems present on principle models (more so during cut scenes) and shading precision seems to dim down when Drake is further from the camera. However, the changes between states is amazing, from wet and droopy hair to mud all over the shirt. The same wet-look is present from the E3 reveal during the cave section as well.
EDIT - As for lighting, which is the foundation of how ANYTHING looks different regardless of (though also due to) shaders on geometry and sprites, when you do a cutscene you have complete control over the camera and thus can plan out and place lights all over the place like you would in a CG movie. These lights are generally not visible other than the effect they have on objects. This is how filmmaking works as well especially in dramatic close-ups, only you actually have to place the lights outside of the visible frame and film "around" it.
In gameplay, you can assign similar lights that keep the player model semi-illuminated in darkness and add to the pop, but if they don't blend into the scene and react to the lighting present in the environment (whether its a lamppost or sunlight through the trees) it would feel out of place and pull you out. This is specifically stated by Naughty Dog as well, and why you won't see every bit of detail at all times on Drake as there are certain things that will cause the visibity of detail to change or even appear in the first place (such as veins, stains, clothing under a wet shirt, muscle / bone deforming skin, pores, etc.)