The permission and security systems will be circumvented by malware authors and unscrupulous developers, just like they are on macOS. Given the enormous amount of personal information on our mobile devices, this represents a particularly concerning potential regression in end user privacy and security.

Like on Windows, macOS and Android it’ll be crucial for users to avoid installing executables from the web. and like Android, users also have to be trained to only install apps from ethical software repositories that respect user privacy and security. This is the best case scenario for privacy/security, and essentially the status quo for Android.

For better or for worse, the days of iOS users installing any and all available applications without worrying about malware is over. Users will get more freedom, but they’ll have to take more responsibility when vetting and running third party apps. I don’t know how a notoriously novice user base will react to that, but we shall see.