They really shouldn't use The Sims 3 as their base.
I remember very well how The Sims 3 was in fact very disappointing in a lot of aspects, its attraction system was not near as good as The Sims 2's, it didn't have apartments at all, just regular lots inside shells from where Sims would come out occasionally, retail? haha it was Store content and it was absoutely barebones, same for restaurants, active careers were also extremely boring, playing generational-style was devoid of any fun whatsoever because there weren't any difference between age groups until Generations and University Life came up.
BUT The Sims 3 had CAST and open world, so yeah, The Sims 3 was a different game than The Sims 2, it was a different experience which The Sims 4 will NEVER provide, the feeling of playing inside an entire city and not just locked to a single lot.
The Sims 4 plays much more like The Sims 2, we are back again to playing a single lot at a time, the experience is back again to being much more local rather than how the sims behave in the entire city, the focus is on the sims themselves, but aside from engine improvements The Sims 4 still lacks an immense number of content that The Sims 2 had, the Sims have no personality whatsoever, they don't have memories, they don't even remember fighting a Sim seconds ago and just proceed to hug each other after an intense argument, they don't have chemistry, every Sim treats each one exactly the same way, there's no drama, there's no fun situations like in The Sims 2, honestly it's kind of sad how the ONLY thing The Sims 4 has to provide over The Sims 2 is technical improvement and an amazing CAS but that's about it.
Now yes, The Sims 4 is improving, largely, now I can actually play Simulation Mode and not want to close the game 10 minutes later, I'm just saying it's useless to say things like "we did X thing better than The Sims 3" when at the end of the day The Sims 4 is just an inferior version of The Sims 2 in many aspects while The Sims 3 will always stand out in its own way to huge features only it can provide.
Oh, and The Sims 3 has cars.