The Bozjan Front is lousy, lazy content

[HollowedDoll]

And Bahamut being asleep in it is somehow more destructive than him adding to it all the explosive power of being very much awake?

Again, look at the effect on Cartenau. Almost nothing. Look at the effect on the nearby regions. Aetheric interference and some debris. It didn't turn anything into a featureless grey that wasn't already featureless and grey.

That Bozja is featureless and grey is because they wanted it to be featureless and grey. All precedents point elsewhere.

One was concentrated the other was spread apart, it did turn Ishgard into a frozen wasteland if anything.
and while I get your point, one way or another they decided to go for a wasteland and the lore was estabilished for it within a reasonable timeframe imo.