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.
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.