Echo?? (a newb loremaster inside)..

[Zetsumei_Tsunarashi]

I know that apparently "we" were teleported away for five years, but that seems like an awkward explanation as five years is a short time to rebuild entire cities.
.

Well given that yoshida's favorite FF game is FF7, and the fact that several facets of that game were used in ARR (materia, meteor, Limit break, gold saucer etc.)

I'm theorizing that the event's following Louisoix's teleportation spell, probably mirrored the events that happened when meteor fell on Gaia in FF7. Something along the lines of the Mothercrystal releasing the aetheric energies (lifestream) within the planet to somehow put a stop to Bahamut's rampage. You'll recall that the last image we see of Bahamut's attack is a flash of white light which we are meant to believe is the result of Bahamut's megaflare. However, I believe that this is infact the moment when the Mothercrystal intervenes. There are similarities in the two scenes as well such as the failed attempt to reseal bahamut mirroring the failed attempt to stop meteor with Holy.

This is why the planet was spared from utter annihilation and the cities remained pretty much intact. Bahamut's megaflare never went off, or if it did, it was blocked by the "lifestream". The cities weren't rebuilt in 5 years, they were never destroyed.

If I had to guess what happened to Bahamut, I'd say the counterattack by the mothercrystal probably resulted in him being frozen in crystal somewhere (the labrynth of bahamut maybe? >.>) and he'll likely break free at some point in the story resulting in a final battle.

Just my guess, we'll see what happens.