It's important to make a distinction between natural / gentle chaos and forceful destruction.
The First is suffering from a lack of chaos - change. The cycle of day and night has stopped. If we go further with that time itself is winding down - people have stopped aging, crops won't grow, there's no weather (except maybe a dead breeze), etc. We need to bring those things back because they're natural processes. How? I couldn't say that - the whole "Warrior of Darkness" thing is still unexplained, and I'm pretty irritated about that after 4.56 giving us no clues as to what's happening going forward (beyond that we're going to the First Shard). Probably by just doing the same things we have done - intentionally or otherwise, we've already been harbingers of chaos in both Ul'dah and Ishgard.
There's a big difference between the gentle, natural change we're supposed to be bringing (back) to the First... and the sudden, violent upheaval favored by the Ascians. Think of it in terms of death - all things die, gently or violently. We're harbingers of gentle death (of the status quo), while the Ascians take a far more extreme and violent route.
Will that change anything about our character? Prolly not.