He ordered the total destruction of an Imperial base, with lots of personnel still inside. That’s not dramatic enough for you?
First I’ll admit that I’m going off memory seeing the film one time, so my recollection of every detail may not be 100% complete. That said, discussing the example you provided, do you think that was integral to the story? Or just filler? If you think it was integral to the story, do you think it could have been possible to have Krennic do the exact same thing? Combining characters and writing a tighter script is a very good thing.
In the example I cited, Krennic obviously can’t relieve himself from his own command. And there’s the issue of Tarkin needing to be in command of the Death Star at some point. I think the script would have been way better with Tarkin and Death Star references without them actually being included in the film. Give Krennic a Star Destroyer and a fleet and let him battle the rebels that way. Let him do all the work.
Leaving the Death Star out of the movie and not relying on its impending threat only visually, I think would have pushed the filmmakers into creating a far more compelling story.