But I still don't think that previous timeline Mia was so bad. Sure, she deserved a punishment, but she didn't deserve to spend years in a dungeon in terrible living conditions just to be executed at the end.
For me there is a difference between "I don't care if the peasants are starving, just bring me more money and food!" and "What do you mean that the people are hungry? Just get more food".
In the first case that person should be detained and locked away. Maybe even executed if a lot of people died because of them.
In the second case that person should be bitch-slapped, forced to attend lectures about the current state of their country, and kept away from any position of importance until they prove they can handle it.
Even if ignorance is a sin, it is still better that active and conscious malice.
Also, it seem that justice-boner prince is ignorant enough on his own. Ruthless justice tend to slip towards evil soon enough