Those are some good points, and I especially loved that lifecycle management in the era where I used a lot of Windows 8 apps. Even on a Desktop with apps filling up my screen still seeing some of them pinned to 0% CPU most of the time (while I'm multi-tasking) in Task Manager was a delightful magic. I also agree that was one of the best parts of the UWP sandbox and one of the biggest shames when Microsoft had to figure out how to allow sandbox breaks that they couldn't find a way to make the lifecycle and other smarts parts of the sandbox more opt-out by default rather than "opt back into the full sandbox". Of course needing to opt-out by default was one of the reasons developers hated the sandbox in the first place. It's a marketing challenge no matter how you slice it.

That relates to some of my criticism that maybe UWP could have used more .NET veterans because that was one of the problems with the CAS sandbox. For the most part the CAS sandbox was "opt-in" and yeah software developers through ego, hubris, and everything else will most often declare "my app/library is a special snowflake and needs access to everything!" So even if things opt-in to additional security controls like CAS, no one tests or builds for Production in a CAS sandbox so even things that claimed to support CAS threw runtime exceptions all over the place to the point no one could trust CAS to the point were CAS died for being practically useless overhead because no one both opted in and knew how to test it.

UWP had a lot of good ideas. It's insistence that it didn't have much to learn from .NET's mistakes was not one of them.