Orrrrrrrrr, add another AI or form to play. Like you have to beat 3 different AI in a roll, these AIs would be like Half bloods, with 100 HP
Hey, that's a good idea !
Or, a mode where you have to beat 10 AI3, or an endless row of them with an AI5 every 10 battles, and a FG every 100 battles...
Or a row of AI5 with FG every 10 battles... you know what I mean.
The reward would not be electrum coins (not more than the standard reward) but a card, common if you beat 5 opponents, big (like dragons) if 15, and rare if 40... sort of.
And where you gain the right to skip an opponent if you have done 1 (or 2) elemental mastery.
Well, new challenges would be great. Along with new cards of course