OK, my theory on this resignation is that Eppler was more involved/heavy handed with the MLB club and no one told Uncle Steve or Stearns. Now that Stearns is here and I'm sure he is talking/interviewing staff and other coaches perhaps players and they are now snitching on Eppler since now he is not the top guy anymore. See this Vogelbach/Showalter story. Maybe that coming out also revealed other stuff Eppler shouldn't have been involved in so the trust is broken and they asked him to resign or be fired like they dud Buck.
Just a theory not at all factual.