I do believe they are revisiting Sims 3 as the sims featured have that same uncanny valley doughy human appearance; it honestly breaks my heart considering one of the best things about TS4 is the return to gorgeous sims without having to download 10gb of CC solely for CAS tweaking 😔 Even if the world is robust, TS3 was the only game I could never actually play because I thought the sims were hideous. Of course this is just my opinion, and I don't want to ick anyone's yum here! We all have our favourite game (TS2 is mine and I use a lot of CC for the same reason).
I will have to say, even though I didn't buy all the TS3 EPs and only played the base game and World Adventures--except for when I got scammed into buying digital codes on Ebay that were apparently bootleg (I was young and naive😅)--I absolutely loved World Adventures because it was about the challenges and not really about the Sims.
I was really hoping TS5 would be more like TS2 in-depth Sim play with a TS3 world that would keep the upgraded look of TS4 or go beyond that. Oh well, it's a good thing TS4 is such an on-off game for me, I have all the add-ons (excluding anything supernatural) and haven't even remotely explored all the features that are in my game, so I have at least 10 years to have new experiences while I see how TS5 turns out from the sidelines.