Long story short: it depends on what point in time we kicked the bucket. Earlier in the story getting a new Warrior of Light would be a pretty simple matter, but after we've established our status as a major player on the Eorzean stage it would lead to chaos and panic.

Exactly what the consequences would be remains a matter of what we failed to do, and whether or not you can predict the causal chain that would follow. At the very least Urianger seems convinced it'll lead to a Calamity...