@Willy Vereb, I tend to be more realistic than most while in roleplays. That's why I don't usually join fantasy roleplays.Actually your "realism" is rooted in popular media logic. If you truly want to be a realist a larger spaceship is always faster than a smaller one. Why? Because you can spend higher ratio of mass on what is actually useful for propulsion.
If the Death Star did move, then it would of taken time to move because it's big as fuck. It shouldn't be moving at the same speeds at a fucking ship. Also, it isn't 'stupidly specific.' Having control of eight planetbusters is overpowering as fuck and you can easily destroy several worlds in one single post. Having one shows that you're the 'big kid' around the universe and nations won't fuck with you.
Anyways, having 8 planetbusters or just one doesn't make much of a difference. At worst that means you have to fight on 8 fronts or if you have sufficiently good FTL in comparison just concentrate all your forces to one place at a given time and steamroll the "Deathstars" in 8 consecutive battles.
Either way eight gigantic ships don't mean drastically higher threat than just one. And destroying planets is not guaranteed. In general it really just matters on your tactical sense. This is why realistically using all 8 of the giant ships at once is something which would never happen. Because it only makes sense for an inept strategist who thinks throwing everything and the kitchen sink at somebody is actually the best way to fight wars.
The actual problem would be if:
1.) He has as many starships as us but all of them are country-sized "Death Stars".
2.) His tech advantage makes the "Death Stars" invincible in battle.
Anything else can be handled by somebody actually starting to think on battles. Deathstars are superweapons and can be fun to fight, IMO.
EDIT:
Interesting is one way to describe my faction.
Believe it or not they are actually going to represent the "straight man" in this mad-mad galaxy.
Their advanced tech is also sufficiently tempered by their peculiar culture and lack of war experience.