There's quite a big gap between "world destruction" and the convenient power of reshaping the level design into something (arguably in Cata's case) more fun.
This is a pretty big similarity between these two stories and it's bigger than any similarity that the seventh umbral calamity has with any FF game.
If you get defeated by Bahamut in FFIII or XI you just get a Game Over and he presumably is successful in destroying the world, which is not what's being described here.
These are both MMOs which required a heavy redesign of the zones from their original release, which were both justified in the narrative by the cataclysmic rampage of a gigantic dragon, considering XIV ARR was already borrowing so much from WoW on the gameplay side how is it any stretch to believe they wouldn't pay homage to it in the narrative when they're already doing a Cataclysm level revamp of the game anyway?
It's not like it's an insult to be compared to WoW or anything, I know it's the big bad meanie game and it's supposedly atrocious in every way nowadays but there was a time when the Warcraft games were renowned for their storytelling, that's why they made an MMO for it in the first place!