All I'm asking is "back in the day", when we first got our hands on Lollipop developer previews, we had to use permissive mode. Over time, through various SuperSU beta's - there was a point where the modifications to selinux were sufficient for *most* apps to not need permissive. Sure, some apps that have not been updated still require permissive mode to be set... So you're saying Superuser does that now?
Personally, I've always found superuser the lesser of the 2 root providers and was a long way behind in the early lollipop days and if they've got to a useful point now, great - though I dare say not without a lot of input from chainfire.