The Executor having reverse engines would sound fine and all, but I think they were made for a more modest space age, not for the age of mass produced warfare of this scale.

I dont think the Empire would even play with he thought of putting that on such a big ship like that, it's supposed to be their Titanic and no force in the universe could stand against it when used in a fleet.

Much unlike the Rebells, the Empire does not belive in small victories..it's conquer or destroy...not live to fight another day.