Removing Saturn was genuinely just a terrible move. I am okay with punishing maybe but only after really looking at what happened on Egghead. Killing an important subordinate like that without fully understanding the situation is just incompetent. Saturn was clearly a loyalist who was personally very offended by Vegapunks betrayal. He always took initiative and even tried fighting the strawhats and personally tried killing Nico Robin. He clearly takes his job very seriously and is passionate. People say that replacing him with Garling sets a message to the Gorosei that they're replaceable, but it actually shows that if you don't have 100 percent perfect results you'll get punished, even if it's due to factors outside of your control(Saturn's plan to kill vegapunk was subverted by Kizaru)and that Imu is willing to reward mediocrity and a total lack of initiative(basically garlands entire life). So if I'm one of the other Gorosei I decide to not take the risk and just enjoy long lunch breaks. The strawhats can do whatever tf they want. Good leadership is actually shown by Blackbeard after egghead arc. He personally explains to Pizzaro why his mistakes were harmful to his goals and why he expects better. Then he personally congratulate Kuzan for having some results,which gives a good message to Blackbeard pirates(as long as I accomplish something useful I can get praised from the boss,even if some things go wrong)