Here's another idea... you know how there are weapons which only damage a planet's conditions? Well, something even more useful would be weapons that only damage a planet's VALUE! (Oh, and allow these weapons to be used outside of combat, like stellar manipulation!)
Actually, perhaps an option for stellar manipulation devices should be to make them combat devices, so you have to actually get in range to use them and can't just set your strategy to "don't get hurt" and then destroy the planet from afar

Of course then the definition of "combat" would have to be extended as you could engage in "combat" with an uninhabited planet in order to change it to asteroids
edit: Oh, and something along the lines of this in SE5's equivalent of Happiness.txt:
This Planet Gifted := 200
Planet In Empire Gifted := 40
In other words, you can't go around trading entire planets full of people without getting them pissed off at you... imagine if the US tried to "sell" North Dakota to Canada to pay off the national debt

(Hey, didn't Dave Barry suggest that once?)
[ July 25, 2003, 06:05: Message edited by: Ed Kolis ]