Iuno I think he's trying to do what's right. It's always been his nature. He really doesn't want the iron throne because he sees all the strife that comes with it. In strategy the longer they wait the more complacent the troops may get in enjoying the peace and not wanting to fight.
And this has always been the beauty of game of thrones, the characters get over anxious,whether it's over confidence, greed, lust or power. Triggerfinger didn't need to turn Sansa against Arya, Tywin didn't need to take his wrath out on Tyrion, Walder Frey didn't have to usurp Jon, Ramsey didn't have to kill his father, Oberyn didn't need to taunt the mountain, every character has a choice but you take the risk whether it's a good one or not will show itself to you.
Nobody is disputing that Cersei is cold hearted I'm saying the vast majority of her woes comes from the damage people left for her to repair.
I think we forget she did everything she could to protect her children and wanted them to rule. She wanted to be Queen and was Queen to a King (Robert). She had to take the iron throne and it wasn't her choice to. She never wanted Tommen or Joffrey to die. I think that because we have so much hatred for the character we forget why they're the way they are and don't want to seek to understand their motives and why they're doing what they're doing. Cersei wanted power yes, but she wanted moreso to protect her family. If we were in her position we'd act the same.
As for Jon, it's ironic he got everything he ever wanted and so the saying goes "For what profits a man if he gains the whole world but loses his own soul". All he wanted was to save his people, make his family proud, find out who his parents were and be someone people would respect in high regard. He got way more than he bargained for and is wrestling with the pressure. It's not much different than Cersei or Danearys who are also dealing with the pressure.