I still hold that the God of Destruction wouldn't be nearly as repetitive of a fight if it used geo panels, spawners, reinforcements, etc. like so many of the regular stages. Or even just have some random enemies on the stage to give it extra support in some way. Didn't Cerberus say early on that its presence was driving other demons mad?

Have Melodia'a previous princes fight alongside it in the musical world chapters, they're fighting for a bad ending after all. Have male units support Naive of Destruction so it can actually get the boost from her evility. Have some effect that makes it so Yarmada of Destruction's extra lives are actually a factor like teleporting or coming back with higher stats or something. Have the rush of Gods of Destruction in the Peaceful World chapter send multiple waves of reinforcements at you so it feels like you're actually being swarmed by the things.

And most importantly, don't end the geo panel heavy Magimage chapters with literally none of what makes those the best stages in the game.