I can't say I ever cared much for cars in the Sims 4, simply because I don't see how they'd be able to implement driving around, not just teleporting to your destination, considering the current limitations of the game. Ultimately, I think most players do want to be able to drive around, but I just don't think it would be possible, so they'd most certainly have to implement cars in more creative ways.
If they were to give us a car themed pack, preferably an expansion pack, then I think they should actually take concepts from the "Car Life", "Work on Wheels" and "Suburban Living" themes, and merge them instead of separating them. They should focus purely on activities involving cars, so something like cosmetology probably shouldn't make the cut for a car themed pack.
This could include, but is not limited to:
- Driving Schools - A large lot that can be visited, where sims can learn to drive by studying and then taking their theory test, and then the practical test. Sims could pay an hourly fee to hire a driving instructor, and can only drive a vehicle once they've passed both tests. Young adult and older sims could also choose a career as a driving instructor, and it could be possible to make it an active career too.
- Mechanics and Workshops - This could work well in conjunction with the handiness skill, so the higher the skill, the better the quality of work. Sims could own their own workshops, and become self-employed as a mechanic, taking on a variety of work for their customers. Sims could choose to specialise in restoration and repair, or dive into body shop customisation and modifications. Think along the lines of Pimp My Ride and Benny's Original Motor Works etc, for this kind of unique customisation.
- Gas Stations - Sims could own and run their own gas stations, which could also work well as an active career. Sims could purchase a gas station that's been abandoned, with the goal to renovate the place and make it thriving business, or purchase an already established business if they can afford it. Sims can choose to take a traditional approach, offering to fill up a customers fuel tank for them, or hire employees to help out, or they can choose a more modern approach and be self-service. Sims could increase profits further by installing charging stations to cater to customers with electric vehicles, or add two types of car washing facilities, either manual or a drive through car wash.
- Dealerships - Sims have the option to purchase vehicles by browsing the web, or by visiting the local dealership. Sims can choose to become a reputable salesman, by purchasing legitimate inventory straight from the car manufacturer but it's expensive, or be a shady salesman, by obtaining and selling inventory from not so reputable sources, but it's much cheaper.
- Car Meets and Festivals - Sims can create a local car meet club, and drive to their favourite hang out spots around town. Sims can chat about various car details, and inspect and admire another sims handiwork. Sims can also attend an annual car festival, where enthusiasts gather to show off their cars, and can enter their car in various competitions to win prize money.
- Drive-In Theatres - Sims can drive their own car to the local drive-in theatre, and watch a variety of movies, complete with soda and popcorn. Sims can attend with family and friends, or can ask their crush out on a date. The classic car WooHoo makes a return, but sims should be mindful if they're in a public space, should they want to avoid any scandal or negative reputation.
- Car Hobbies - Sims who are fans of racing can watch their favourite motorsport on TV, with a new motorsport channel. Sims who are the creative type can purchase a variety of car model kits, assemble and paint them, and put them on display or sell them to collectors. Gaming enthusiasts can participate in e-sports races, with a new racing simulator, complete with a bucket seat, pedal set and steering wheel.