I think we would have need more informations about who really killed her parent and why ?
She doesn't seems as "rich" but if i'm not wrong, her parents were just some soldiers, so it's most likely that a Nigh Raid did really killed them. What would have been touching though, would have been to let her realise that the society was wrong, and her parent did the wrong choice even though they may didn't know about the Minister intentions.
Then, Mine could have make a raprochement between her and Seryu. They are kinda the same, they just believe the other side is wrong, so they kills enemies from the other side believing that. They both lost friends and their life were ruined after all.
What would have been touching too, would have been Tatsumi explaining what was Ogre doing, what Stylish intentions were (didn't care about her, just wanted to do experimentations) and that pretty much all of the actual governement didn't care at all about Justice and just wanted the power.
But hey, it's the problem with these kind of fight, the character will focus more on trying to kill the enemy (which is understandable) than explaining anything to him, except why they want to kill them.
Anyway. Every death felt pretty sad to me, nobody really had to die, they just had to understand things. Seryu was one of the worst alongside with Bols because they both thought that was they were doing was necessary for a better world and just couldn't see the despair of the actual humans. It's quite sad.