That's why I suggested having it at the end of the game, so that it doesn't spoil the story, but it does let those who'd like to continue playing with their level 50 demi-god. I'd envision that you beat the big-bad, the final cutscene and credits roll, then it returns to the game where you can continue to have fun. The story has most certainly been finished, but you can continue further if you desire.
I wasn't thinking anything quite as elaborate as a skirmish control panel, just a single button the re-randomises it. But now that you mention it...
