Sorry, Antilliles, but I've also done that strategy and it has worked. You're not alone, but, even so, the game hates me. Even so, I think that blowing up a planet (both realistically and tactically) is probably the worst tactic possible. Psychologically, it'll freak the sh*t out of people, but it's not worth it when you consider the amount of resources, people, goods, etc you lose and the fact that a Death Star can be defeated easily. Use them for intimidation and fleet combat, but I would never suggest using them to destroy entire planets/systems...unless you're evil.