A really nice and simple addition might be to be able to arm/disarm a system from the drop down screen where you view all your systems.
If I look at mine, when I hit the drop down, I see three systems, and it would be nice if there was an arm/disarm slider right there. Already says armed/disarmed so it doesn’t seem too much of a stretch to allow arm/disarm of one or more systems there, if the armed/disarmed notification was replaced with a slider for each. That would still show if they were armed or disarmed, but you would be able to toggle from right there.
Like this:
Seems very simple to me.
Better would be able to group things into your own scenes, but this would do as a quick start, for faster arm/disarm of one or more systems.