Well, if the player doesn't have latest add-ons, it's easy to think the following features came in The Sims 3 and 4.
- Seeable neighbors.
- Lot info panel (where you can see lot value, type, and size).
- Diagonal room building tool.
- Sledgehammer tool to delete things.
- Ability to rotate floor tiles.
- Storing food to a fridge as leftovers so it can be eaten later.
- Pay all bills interaction.
- Ability to paint pool walls and floor
- Ability to have different hairstyles in different outfit categories.
- Accesories.
- Ability to move paintings up and down the wall.
- And lastly, solar panels and wind turbines that lower the bills (in Mansion and Garden stuff).
Though a less noticed thing that first came in The Sims 2 is weekdays. The Sims 1 doesn't have weekdays, thus sims have to go to work/school every day.
That reminds me. The ability to turn off aging is also something that is in The Sims 2, though while future games have it in the options menu, it's a cheat in The Sims 2.
Creating a world is also something that some short of first appeared in The Sims 2. If you have SimCity 4, you can create road and terrain layouts for your next neighborhoods.
