The problem with high detail textures with cel shading is that it makes the cel shading look like a crutch for subpar graphics, even if it isn't. Cel-shading is meant to be used as a stylistic choice to lighten the GPU load on a game, but generally speaking people find cel-shading with realistic textures to be really muddy and gross (just look at the new Tony Hawk game's recent attempt to use cel-shading)
That being said, simpler textures, models, and overall graphics have absolutely zero impact on how realistic the animations would have to be, that's only if you change the actual proportions of the limbs and such. Many 3D Indie games, for example, focus on highly detailed animations to compensate for the graphics being literal stand-in graphics and simple templates.