I love these kind of questions. Feel free to pose your own questions as well, but be sure to put a hypothetical point to each of these five scenarios, and how they would have affected the thread as a whole.
1) What if Exemplar never existed?
2) What if Valeria had stayed in her original character?
3) What if Yitur had succeeded in killing Iko in the Battle of the Tower?
4) Ignoring situation 2, what if Valeria had died in The Angel's Absolution, by Shobatsu's attack?
5) What if Roeh had stayed the course of an antagonist?