I have to say, I'm really looking forward to the Sims 4.
I love the graphics, they look cartoony but with a touch of realism and remind me alot of the Sims 2.
I really like the way you create your sims, and the fact that now you can modify more stuff like the bootie xD
Build Mode looks nice and easy to use, it would be cool if there is a "Turn Off Snap to Grid" mode, for advanced builders. Which lets you put objects anywhere not being constricted to the square grid thing, and also being able to rotate them and make them face any direction.
Would be cool if the same was applied to walls, and with the ability to make a circular room.
And I would love them if they added different shops ( not rabbit holes ) like Clothes Shops ( Like in the Sims 2 where you had to buy more clothes and not have all of them available when you use the Plan Outfit thing like it is in the Sims 3 ).
Plus this Emotion thing is sure to make the game feel more alive and dynamic.