Reminds me of Hamlet's Soliloquy.
"Whether tis nobler in the mind to suffer the slings and arrows of outrageous fortune, or to take arms against a sea of troubles. And by opposing, end them. To die, to sleep..."
The princess chose to end her suffering but, like most of Shakespeare's tragedies, the answer doesn't seem to be clear cut.
Like Hamlet, Othello, and Romeo and Juliet, Effie the Princess committed suicide not from her own decisions, but from the pressure of the situation she was in.
Was it right? She clearly could have lived a life in destitution or exile. The Emperor gave her a choice to commit suicide or suffer through the supposed "shaming" Paulina alluded to. She would have to suffer the consequences of her father's actions and carry that burden with her.
I don't think it was right, if the Emperor knew her innocence. Again, as someone said in the comments, it just paints him in the same light as the other despot Kings. No better than the man he just killed. Forcing her to commit suicide is just murder without getting his hands dirty, low in my eyes. I cannot say I can continue to root for him from this point onwards.
Death is final. And innocent blood cannot be unshed. Does this make the Emperor more complex? Perhaps, but it has come with the cost of his integrity as a character. He doesn't have morals and looks as though he cares only for people if they are of use. That's far from what I would believe a leader or protagonist of any sort should be.
It goes against the ideas shown throughout the series: that everyone deserves a second chance at life and happiness (i.e. Paulina).
The tonal shift was unnecessary by the way. That made me drop this, not the suicide. Makes everyone look like psychopaths rather than humans by doing romcom stuff right after slaughtering everyone.
Unless the Emperor was Deadpool or something.