Most of your suggestions are random and uncontrollable events with very bad outcomes. That's typically not what makes a game more fun.
Also, regarding warning about events, I don't see the point. The game always sends raids your way, you should always be prepared for it. There's no such thing as downtime on the higher difficulties.
Also, regarding warning about events, I don't see the point. The game always sends raids your way, you should always be prepared for it. There's no such thing as downtime on the higher difficulties.