GCW era. death star = wins battle on coruscant.
You keep saying the Deathstar is the Empires super weapon and that it could wipe out a flood infected world like its the perfect solution. Here is a scenario = The flood get a few creatures down on a planet, and like a zombie infestation the world slowly starts to turn. The empire destroys it with a blast from the Death Star. Here's the outcomes I see from this...
1. If any type of evactuation was done to save the planet's inhabitants, the Flood could spread throughout the Star Wars planets easily. This would mean pretty much the end of every world that they evacuate to.
2. No Evacuation, the Empire just vaporizes the planet. Any general with half a brain on the Halo side realizes all they have to do is make it look like there is an infection on any planet and now the Death star is blowing up its own worlds left and right... or fear the death of their races.
3. They spend so much time and resources trying to defeat the infection and the Flood that they get blindsided by the UNSC and Covenant Fleet.
Oh and when worst comes to worst for the Halo side, they could just pull a MAD (mutually assured destruction) cease fire with the rings and the Ark.
Good... Bad... I'm the one with the gun.
Hail to the King Baby!!