1) A game with too many restrictions for a sandbox life simulator game.
2) No Create a Style
3) As in 1) apartments are way too much restricted in build mode.
4) Too many Small worlds and few big ones.
5) Cannot customise neighbourhoods at all / rotate lots, etc.
6) Sims with just 3 tratis. Why?
7) Emotion system is a disaster:
- All sims behave exactly the same.
- Emotions can be modified very easily.
- Emotions can ruin your story if your sim is supposed to feel in a determined way but he/she just shows the other way because the effect of an object nearby.
8) No swimming in lakes/oceans/seas/rivers except in Sulani.
9) Multitasking should be redone: sims getting up during a film and block the screen, sims eating in the toilet, sims getting up from the chairs for no purpose...
10) No Story Progression. Incredible but true.
11) Too many stuff packs.
12) Life mode is boring, nothing out of the ordinary happens. When I play TS3 people just die more frecuently, they argue on the street, they fight, you can be robbed.... it's.... LIFE.
The Sims 3 was very ambitious with the open world, Create a World and Create a Style and the game was full of bugs. But we have to keep in mind that modders fixed many of them and if you use these mods, you can play the game perfectly well. I can tell you this because I'm still playing it and some years ago I couldn't. So if modders can fix many of the unfixed bugs, EA/Maxis can. An open world is possible with few bugs. The problem is the time to implement a good coding, and time to test it thoroughtly, and time to fix possible bugs. And time means MONEY.
We all already know the problems of the base code of TS4 and the limitations generated by this awkward coding (besides the limitations devs add to the game to avoid performance issues).
I hope that if there's a Sims 5, they mix the best of TS2, TS3 and TS4. It's possible in terms of technology and programming, but it will take time to create a good base game that can be flexible for the future packs.