Hi there! I've been studying Frederick for about 3 years (not for academic purposes, but I still think that I may be able to help you) and I can say with a fair amount of certainty that Katte's death had a large impact on Frederick's attitude towards many things, including the military. Frederick's father had been the one to believe in a strong military and a soldier's lifestyle, but Frederick had always been more interested in the arts. Katte's death was actually controversial throughout the entire kingdom, as noblemen were rarely executed; Friedrich Wilhelm went so far as to threaten to cut out the tongue of anyone caught talking about him. At the time, rumors had been spreading about Katte having an affair with Frederick's sister, as well as (much more likely) rumors of an affair with Frederick himself; these rumors may have had an influence on Friedrich Wilhelm's decision to invoke the death penalty, though Tim Blanning writes of Friedrich Wilhelm's admittance that he intended to "take advantage of this anticipated mental breakdown [the fainting, fever, and hallucinations following having been forced to witness Katte's death] to lead his son into the consoling embrace of Christianity." Tl;dr: Frederick showed little interest in military affairs prior to Katte's death (this is not necessarily to say that he found the matter unimportant, merely boring.) However, after being more or less brainwashed and psychologically tortured, he changed. Thankfully, he still retained great interests in the arts. Of course, Katte's death likely influenced Frederick in another way: to my knowledge, less people were executed under Frederick's reign than his predecessors. (This is my own personal theory, though; it seems as likely as the popular "Frederick abolished torture due to his father's cruel treatment" theory. I will be happy to provide statistics from 1775-1778 if asked.) I'm sorry if this hasn't been very helpful; I've only been a history major for about a year.