RPG endgames should shift paradigms

There is nothing duller than a level 300 boss, except levelling up your entire party to face her. Instead of Yet Another Tibetan Yeti Elemental Zombie Hive Queen, what about an end game where the party has to solve a puzzle, especially a puzzle they've been working on for the last 500 levels? More Myst, less Bahamut, toward the end?

Ah, don't mind me, I'm just fuming about Gilgamesh, who appears throughout the Final Fantasy franchise, and seems about as annoying as Indalecio ever was.