I'd love more careers! I enjoy working up the levels and receiving the promotion unlocks. I'm inspired to create a lot of my Sims based on their career choice.
Would like to note that a couple of the careers listed thus far would unfortunately be tied directly to DLC, which would likely create another My First Pets Stuff snafu, DLC for DLC. A Meteorologist career would be directly tied to weather in Seasons EP. Devs would have to get creative and think outside the weather box. Without Seasons, it's always sunny in Willow Creek. Dog walker = Cats & Dogs EP. Both of these careers would be fun, but I'm not sure if possible to implement.
It would be cool, however, to introduce Career Stuff packs to invite more career-focused gameplay, CAS and BB.