I would truly love to see:
More badges; maybe for 100,000 gold, x thousand enemy kills, certain stats at x00, etc.
I find myself continuing to play, long after I know I can easily wipe everything. It's a nice break from having to pay attention to complicated battles.
It would be eternally cool to add some sort of expansion to this, perhaps change the story at the end where The Merchant, in his rage, casts a spell on you, sending you to a different location, making you work your way OUT this time.
 "The Enchanted Cave"){kind=icon}
 "Billy the Pilot"){kind=icon}
 "The Magic fairy"){kind=icon}