In Legends, it is known that Palpatine is aware of the Yuuzhan Vong's presence in the galaxy since before the Clone Wars. A pro-Imperial in-universe book published in 55 ABY is quoted as saying:
I am baffled by critics who accept Mitth'raw'nuruodo's account of his discussion with Palpatine about the Far Outsiders, yet refuse to revise their opinions about either man. They ignore what Mitth'raw'Nuruodo reported Palpatine believed: that the weak Republic would be defeated by the Vong, and had to be reforged into an orderly, militarized society able to resist them. They refuse to consider the possibility that the Empire's apparent brutality and ruthlessness were necessary parts of preparing for that terrible war. Why do they refuse to do so? Because that would lead them to the only logical conclusion: that Palpatine was right.
With this revelation in mind, the question comes: How much did the coming Yuuzhan Vong invasion influence how Palpatine ruled his Empire?
After all, it is suggested that the Empire's militaristic rule served to strengthen it against the imminent extragalactic invasion. If the Yuuzhan Vong never existed, would Palpatine have ruled with a softer hand (as counterintuitive as that sounds to a Sith Lord, nobody said they necessarily have to be tyrants if they already possess popular support), maintaining only what is necessary for internal security and to exterminate the Jedi?