This could potentially work for Sims 5.
Way back in the Spore days, Maxis spent who knows how much money developing the tech to create procedural animations: that is, the shape of the alien (or Sim) determines how the animation plays out.
It wasn't used in TS3 or TS4, so I don't think it's likely to be included in TS4 (as they would have to completely re-do every animation in the game) but if they had the opportunity to start from scratch with a new game, then I could see it happening.