I think the most tragic part of Ever Crisis giving us Miniroth is that we see just how good he was.
We crack jokes all the time about how much of a puppy Zack is, but Miniroth is arguably only a few degrees off from him with some RBF. He cares about doing good, about protecting.
Knowing that that's his starting point makes the build up and eventual culmination into full on break down and the Nibelheim incident just have a bit more of a knife twist to it. Cause now we know it's not just Angeal and Genesis that he lost, and he hasn't always been the stoic, refuses to get close to anyone aside from Genesis and Angeal SOLDIER war hero.
We've gotten a broader scope of just how great of a man Shinra, and to a great extent specifically Hojo, robbed the world of for the sake of their end goals and bottom lines.
I don't mourn the Sephiroth that summons Meteor to try to clean slate the planet. I mourn the man he could've been instead.