Doesn't that sound like a great newsletter? A newsletter has to be useful or interesting. Both is what you're aiming for. It won't be useful if it isn't interesting enough to read.
It doesn't have to be long, full, or detailed. It doesn't need to be chock full of advice. It doesn't need fancy graphics and eye-catching colours. While any of those things may help achieve your goals, they aren't necessary. In fact, it doesn't have to be about the content at all.
Think back to that top secret briefing. There's one attribute I left off the list above that makes it ultimately useful. In fact, it would be useless without it. Did you guess that it's the speed of delivery, or timeliness?
Can you imagine the busy White House staff working all night to prepare each issue? Spell-checking and spam-checking and tweaking the template... NOT! None of these things are as important as speed in this case.
There are many attributes that can make a newsletter successful. Sometimes it's not the content itself but rather the way in which it's delivered.
A great example of this is a daily newsletter sent out by my friend, The Gratitude Guy. It's not so much about what's in it but the fact that it reminds me every morning to stop and be grateful for something.