For those of you that have root apps out there, there was an AOSP commit for full implementation of SELinux with the next version. That means that you won't be able to execute scripts from your app except when piping them through su directly, like in normal linux distros. So if you haven't corrected your code yet, it's high time, or the app will stop working.
For those that use apps on a rooted phone with non-custom firmware, make sure you don't depend on your root apps for backup and restore for instance, because it might well be that with the next stock ROM update, these apps won't work anymore if the devs haven't corrected their code yet.
Full SELinux implementation is great though. After Samsung some time ago, Google has now decided to activate SELinux implementation in the next AOSP update. Thanks to SELinux, Android phones will become a lot safer to use. It might take some time for root apps devs to correct their code though.