I'm hoping it's Dine Out. Restaurants are a bit quirky at the moment. Having the ability to choose specific staff rather than just random townies would be a great improvement. Perhaps some behaviour adjustments for Sims on the lot too, fine dining should warrant a different "vibe" to your local burger joint. Maybe that could be based on how the food menus are set up - a clientele switch for formal vs casual?
I think time should run at a lower speed while dining just to compensate for the amount of interactions. It's kind of the opposite situation to when your Sim goes off-lot to work, then comes back after X hours with their Needs all mucked up. It should only take a couple of hours to have a full 3-course dinner for 2 people. A quick single course should take less than 45 minutes.
Integrating Gardening into Dine Out would be a fun addition. An option to sell produce to a restaurant which unlocks perks for that Sim. For instance supplying them with sufficient above-average produce gets you 50% off dining. Bump that quality level up to perfect, and you eat there for free.