Live Internet speed monitoring or meter - most smartphone brands have this I don't know why Samsung haven't added this yet.
Applock - Another very basic feature. I know about Secure Folder and I love it but that's more like a separate space than a simple app lock. I don't want to install 3rd party app locks. Samsung should add an inbuilt app lock too.
Improvements in the camera algorithm - Photos taken under low light conditions are often very noisy and grainy. A fix for this would be nice.
