Changing the Auto-Light Upgrade on fireplaces so that it only comes on when the temperature outside is cold. The fireplace isn't usually required in Summertime
Being able to change fire color - They had this feature in Sims 3 and it was great. The RoM fireplace already has blue flames, just wanna point out
Designating sinks to Kitchen or bathroom so we can stop Sims from washing dishes in the bathroom sink
Designating Front Door, Back Door
Adding outdoor wreaths as holiday decoration choice and being able to place it on front doors
Doorbells and being able to choose a sound effect
Tuning Piano, Guitars and violins
Adding Grandfather chimes and having them chime every 6 hours. Winding the clocks as well
Adding bird effects and the ability to fill with water, empty and clean the bird baths
Adding an electric blanket upgrade to beds
Build/Buy
Porch Screens and Screen doors
Porch Swings
Awning tool or being able to place an awning and then drag to make it bigger
Tent tool to build a big tent for say a Great Gatsby Party and then little accessories to make it grand or to give a certain aesthetic feel like a Medieval Fair, circus, or a wedding
Dog houses and cuter beds
Security Systems
Gameplay
I think you should give the Mermaids a Trident to play to find like a mini quest. Give the Trident expandable powers for them.
I think you should have cross creature dueling.
Bring back dogs as ring bearers that was dumb to scrap that
Burglars but make them a tad more sophisticated
“All mushrooms are edible, but some only once.” Terry Pratchett