What Happened to The Sims We Loved?

Sims 4 has been much better balanced the last...like, 6 years. They've been doing a lot better with the game requiring actual effort. Motives decay too slowly, but that's about it TBH. A lot of things are pretty well put together whereas at launch you basically barely had to do anything to "progress".

I say this as a modder whose main modding is focused on balance adjustments, but I like the game much more challenging. The Sims 2 is really not that demanding once you have furniture above the level of a starter home, though.

We miss meaningful emotions, the tough curveballs, the unexpected twists of fate. 

You mean like Sims suffering Grief from deaths or losing a job, experiencing looming layoffs that may progress into a layoff, and the grieving process making them become a glutton and overeat when before they were a staunch vegetarian? That sort of thing? Cuz that's what the last few packs have been giving us, we definitely get that stuff.

Why don’t neighbors react when I behave badly? Why does a breakup leave no scars?

They very much do...Sims literally react to bad behavior. With get famous you develop a reputation. When you've broken up with someone you'll get memories of them from milestones from growing together that make you upset, or with other packs they may call you and beg to get back together, or being near them out and about in town will make you uncomfortable, and with life and death you can get grief from a breakup. That grief can be anger, denial, or sadness dependign on their traits, and if they've had grief from a breakup in the past, they'll get a special kind of grief from having lived it once before. These ARE mechanics. You not knowing about them doesn't mean they aren't there. These systems are DRAMATICALLY more complex than they were in Sims 2.