- Wide support in macOS for sharesheet-style extensions, along with better built system supported extensions (why can’t I copy links this way in every app?)
- Meaningful improvements to Mail.app. It’s still the most stable mail app, but it feels really stagnant.
- A unified language for app design, such that the macOS native look and the iOS native look begin to converge. I care a lot about the usability standards on macOS, but the actual look of a standard “mac app” is aging. Also, there’s little precious about that compared to things like standard Menu items and shortcuts, how the title bars work with files, etc.
- New entitlements, widely available for Mac App Store apps.
- Improvements to performance monitoring, maybe even some options to allow macOS to kill apps more aggressively ala iOS that can be optionally turned on. I want to know more about what is crufting up my system and I want more incentive for apps to be better written.
- New tiling options for window management rather than just full screen or full screen L/R.