I would like to see something like a "tripwire" added to the game, which has an email or phone number associated with it. When someone attacks your base and trips the wire, you get a text or email message.
You work hard to make a base defensible, but then some dude comes along while you're offline and spends 2 hours left-clicking his mouse to crack through your walls. The whole time, you're supposedly inside the base but you don't hear this. So you logon and find hours of loot gathering work gone, and you never even had a chance to defend yourself. It's very demoralizing.