Isn't that kinda the whole reason behind Mustang wanting to become fuhrer (and in the end restoring relations with the Ishvalans)? They all seem haunted by their past and want to right their wrongs, as opposed to someone like Kimblee who was also a war criminal but was the opposite of remorseful lol

I mean sure, but they were talking about it while in ishvall conducting a genocide. They were given very clear marching orders to do genocide and kill every civilian they saw. Reluctance does not get you bonus points. A just outcome would be all of them in front of their equivalent of the Hague.