Another possibility is that due to the deaths of all but one Sith Lord, a lot of knowledge was lost to the Sith, and it took a thousand years to rebuild some of this or steal/find holocrons that have the knowledge needed for the likes of Palpatine to grow his Empire.
Just as the Jedi are able to acquire Sith artifacts, so are others. And with the intel network the Sith have set up in the galaxy, it isn't too hard for them to reestablish an archive of ancient texts. (For "idea" reference, I recommend reading Path of Destrustion)
The Empire's ships were always sterile.
But no less rugged, and were always battleship grey. NOT WHITE. Except the Lambda Class Shuttles.
But they were sexy so who cares?
If the likeness is good, damn good, then to me it's a tribute to the person, IF that person is no longer alive. That's how I felt with Paul Walker in Furious 7. It honored him and the character he played.
If that were the case, they should go back, undo the mistakes of my least favorite SW film, and rewrite Leia properly as a Jedi.