Are there skill challenges for skills like in Sims 3, so you can supermax a skill by also completing the challenges? Or something else instead?
I haven't seen a skill challenge,
per se, but skilling seems to be integrated into other aspects of game play in a that sort of fills that void. For example, instead of having Painting skill as a metric for the Artist career, your next promotion may be dependent upon raising the skill two more levels. Or, when I started a Comedian Sim, the first two requirements for completing the Comedian aspiration (not sure the name - "Joke Teller" maybe?) was to make 10 acquaintances and 5 friends.
Fitting that type of activity into a challenge ruleset will require some finesse, but as far as straight gameplay, the element is still there, I think.
Goat