It is because it is based on Illusion games, which provide the animations, rather than people using rendering studios like DAZ to make the animation frame by frame (very surface knowledge on my part, might be wrong).
So look for games based on honey select etc. Some of those games have only stills though, or the animations are just what you get in the base game without any mods etc, which ends up pretty lacking.
Insight of you is definitely the top for me, as far as animations go.
While the game has gone to shitter with weird development times, Twisted world seemed to have a dev that spent a lot of time with the animations as well (also based on an Illusion game I think).