Just sort of a "What if" thread. Let's presume that the plans still leaked and most of ANH happened, but with Krennic somehow in command instead of Tarkin. What would be his relationship with Vader? Would he have destroyed Alderaan? Would he have "evacuated in our moment of triumph"? He generally seemed to be far more impulsive and quick to anger than the mostly cool and methodical Tarkin.
One thing that would have been different for sure would have been Vader's role. Even with Krennic holding rank on the base, Vader would not have been subordinate to him. Vader clearly intimidates him in a way he surprisingly did not Tarkin, and for that reason and maybe others Vader clearly held a respect for Tarkin. He displays none of that for Krennic, so even if Krennic held a higher rank on the station, Vader would be in control. In such a situation I still think Alderaan gets destroyed to make a point, but, I would entertain a higher chance that the Death Star might have escaped destruction. Vader was much more willing to entertain ideas that the DS was not the end all be all that could be exploited. Tarkin's flaw was that he just would not seriously entertain a threat. I think this would have resulted in Vader making Krennic be, at the very least, more careful in the planning and maneuvering of taking out the rebel base in this regard.
I agree that Vader would've probably pushed Krennic around. I'm not sure if Alderaan would've been destroyed or not; it was Tarkin's idea and it's a big question if Krennic and/or Vader would've thought of the same idea. I kinda wonder if a what if of this would've had Kenobi, Luke, and the droids arriving on Alderaan, Han and Chewie leaving for their next gig (unless other unforeseen circumstances brought them back), and the movie being more of a "hunt for the Death Star" and "less of escape from the station we stumbled into."