Currently The Sims Official Magazine is being released and of course there is a page devoted to The Sims 4.
You can find it here: http://thesimsofficialmag.com/issue4/sims4 (refresh it a few times if it doesnt load)
There are two paragraphs that are very cool:
Whims, Traits, Aspirations
We’re used to crafting Sim personalities with Traits, and those of us that played The Sims 2 even remember when we used to control their Wishes. The Sims 4 lets us get to know our Sims’ thoughts and feelings not just through Traits, but through Whims and Aspirations. Whims are like the thought bubbles that come up when Sims are out in the world doing stuff. They’re often something a Sim wants to do in the moment, like mix a drink or play with a chess set. Fulfilling a Whim grants the Sim something like Lifetime Happiness points to spend on rewards.
Aspirations are more long-term Sim desires, similar to the Lifetime Wishes from The Sims 3. A Sim might want to master a certain skill or career, or own certain items. Unlike The Sims 3, which limited players to only one Lifetime Wish, the Aspirations in The Sims 4 are organized such that every Sim can have as many as he or she wants. Once a Sim completes an Aspiration, they’ll get the corresponding Aspiration Trait that goes along with it. A Sim that becomes a master chef, for example, will get a cooking-based Aspiration Trait.
A Sim can have as many Aspirations as they like, this makes me very very happy. After I complete my Sims’ aspiration in The Sims 3 I quite often get bored and start up a new family. I also like the sound of Whim system (Note: They do stay with the Ws in The Sims games: Wants. Wishes and now Whims).
I am also curious how many traits we can have have eventually. I can see myself bouncing from one aspiration to another to get as many traits as possibile!