They had a falling out over something petty and he relegated Walsh from one of the best match day assistants in the league to out of the coaches box and into a forward opposition scouting role, which is why he left. He didnt want to leave Port but felt he couldnt work with Williams any more.
I still think coaching is pretty straight forward and old school. Its all about respect and you look at the premiership coaches over the last 10 years and they pretty much all look like they'd throw you down a set of stairs if you talked back to them. Its why others like Hinkley, Lyon, Eade have had teams that play for them as well. Its also why the 'ill be your best buddy, you can tell me anything' guys like Sando, Watters, McCartney, Primus, Voss, McKenna are more suited to assistant/development roles. If Walsh does get it, you will have a coach that the players will want to play for and will thrive under imo.
Im hearing he may not have been offered the senior coaches role, but a DOC/SA role, if thats the case, I dont think Port would stand in his way either.