If I were a game developer, I think I'd want people to make a list of stuff in the sequels that were not in the previous games.... not the other way around...
But anyways, there's a post on Reddit with a yet-to-be-expanded list of stuff missing from The Sims 4 - link.
Seriously, EA? I thought this was a sequel, not a pathetic excuse to try and make the game compatible with weaker systems. I don't even think you achieved that goal, because The Sims 4's system requirements are more or less the same as the ones in The Sims 3. And in your failed attempt to reach that goal, you butchered the game so heavily only the most diehard of fans would buy your game. I'm not one of them. And you cut all of that for what? Sims being able to die from being too happy? Give me a break, EA! Give me a break! Can't you see that you're ruining some of the greatest game series in existence? You're not making yourself look very good in the public eye; in fact, you're making yourself look like a laughing stock. Is EA going to be the corporate-version of Rob Ford? Yeah, I think I've seen enough stupidity in my life. Seems like the perfect plot for a movie, where the toxic chemicals in our everyday lives have affected the amazing human brain, and all of a sudden people are just being dumber, making the silliest of mistakes that even a martial arts master couldn't help but gossip about.
/RANT MODE OFF/
EDIT: Confirmed - EA has butchered family trees in The Sims 4 - . Talk about going backwards instead of forward. I think EA drives their cars backwards all the way. Backwards down the highway, backwards down a busy street, backwards into the parking garage, backwards into their neighbor's lawn, backwards into their neighbor yelling at them.