NeverarGreat said:
Furthermore, in the case of Tarkin, he distracted from the primary villain: Krennick.

I would say the main villain was supposed to be Tarkin all the way, and then Krennick was created just because by the very premise of this movie, the villain would have to be defeated and shown as incompetent, and going by his rank, position and reputation in ANH, Tarkin wouldn’t have been the case.

However, a Star Wars movie centered around the Death Star one week before the beginning of ANH without any trace of Tarkin would have raised a lot of questions as well.

I think the solution they found to solve this issue was, among many other things, elegant, regardless of how good CGI was.