Oh boy.
So my friend started playing with Sims 4 and the difference between my perception of the series (started playing when I was 7, have played all titles extensively) is wildly different.
The Sims 4 is only fun with mods. Not just CC to make your sims look pretty, but actual gameplay introducing mods. Even then, the sims themselves can only carry the additional gameplay so far. My friend and I play Sims 4 with WW, basemental, etc. etc. etc. Does it make the game fun? Sure. But it feels more like GTA and less like the Sims.
I have been having so much fun with Sims 2 recently that even returning to Sims 3 is hard, much less Sims 4. (Granted it doesn't help that my PC is low-end, but I digress). The ONLY real mod I play with is ACR, because it makes romance sims more fun and more challenging. Of course I have CC to make my sims ~beautiful~, but I'd still play the game without any.
The sims themselves feel so much more alive than in Sims 4. They're the most expressive in the most realistic way. Even though emotions were treated as revolutionary for TS4, they have gone alllll the way back to TS3 (moodlets) and TS2 (implied emotions). In the Sims 2, even though I don't have text telling me "so-and-so is feeling tense" because she's a sloppy sim I forced to clean, she complains, slowly trudges to the task, sighs when she's done. It's not super theatrical, but I can still tell what is going on with my sim without it being spoon-fed to me. And that's the first key difference: Sims feel like real mini-people in Sims 2. Like others have said, sims in Sims 4 are like animated barbies with a lot of text attached to them.
The other key difference is that Sims actually want to do something with their lives. In Sims 4, the sims just kind of idle around the house and swipe on their phone. Their "aspirations" are just a checklist of easy to obtain and superficial goals. My simself's aspiration, AKA her dream for her entire life, was to have a lot of columns. I go "okay" and give her some more columns. Life goal achieved.
Even if I can change her aspiration later, it makes them have no depth or purpose. My friend, who started on TS4, doesn't quite understand my disappointment at having sims that just float around until you force them to do something (they'll probably like) because for her the Sims is about forcing mini people to do what you want so you can watch it happen.
On the contrary, my Sims 2 sim is a romance sim. So she's juggling five boyfriends, has a daughter (thanks to ACR) from one of those boyfriends, and thanks to her wants and fears I know that she has no plan to stop and WHO and HOW she wants to keep going. On top of that, she has a random Lifetime Want that's completely unrelated: to be a celebrity chef. I didn't choose it, I had no clue creating her that my gothic playgirl would want to pursue the culinary career, but I based her career and skill-building off of her want. And that's what I love about the Sims 2. Even though you have some degree of control in CAS and as the player, your sims still seem to have a personality and mind of their own. With a romance sim, chemistry is another amazing addition to this feeling. Sometimes, when I don't see any sims that are to MY liking, I let my sims scope the room and pick for herself. Even though I'm usually veryyyy disappointed in her choice of strange-looking townie, I respect her decision.
These are just the two BIG reasons. The lore, small details, aesthetic, memories, and so much more all contribute to The Sims 2 being my absolute favorite.
TLDR - The style of gameplay that I've grown to love is a trademark of The Sims 2, but not possible with Sims 4. :)))))
