I'd love to see them in The Sims 4. Perhaps they could be option that you could enable in the game play section of game options, that way people who don't like the idea of them would not have to play with them. I think that the game could do with more of those sort of options.
Things like vampires and spellcasters for example can be polarising. Vampires breaking in to feed on sims and magic being used outside the magic realm would be examples. I would like some of the things that could do that would make the game a bit less static, but still have them avoidable for the people that absolutely hate the idea of them.