The way I see it, you can solve this problem by getting my potions in an honest/fast way or getting my money . . . here are some ideas . . .
10.) Make 100 stamina boards that take are awesomely difficult.
9.) Make special boards that are high energy cost that DO NOT allow revives as a condition.
8.) Make a store so high level players can just buy cards. Personally, I don't recruit anymore because I always get junk. Now, if you let me buy an 8-star Apep for $100+ I would do it.
7.) Make 100-200 new cards with 500 gems each, all good cards, and let ONLY those cards be in the recruiting pool instead of old junk
6.) Make a super board with a SUPER cool boss card, and let that boss steal energy potions from you up to certain limit like 10 per board.
5.) Actually take our advice, make King Solomon, and sell him to us. We will buy him.
4.) Make super cool ranking dungeons that are 100 stamina, with near impossible bosses, and let us complete to get top scores and prizes for beating bosses within a certain time limit or doing highest damage
3.) Allow us to exchange energy potions for gems. Say 10-20 potions for ONE gem.
2.) Then, after #3, make boards with again new actually cool cards that cost GEMS to play, not energy. Make these boards last only 60 minutes and appear once a week.
1.) Implement any sort of system that will encourage us ON OUR OWN to spend more potions faster.
FINALLY, get more creative with the game to make us WANT to give you our money! Making a "poll" to basically take potions we have spend thousands of hours mining for -- for me personally -- breaks the trust between the players and the developers. Then, I think, what will they do after this? How much longer will this game even be around?
And here is another idea, let us SPEND POTIONS to take junk cards out of the recruiting pool. So, hey, I don't want to see that three star Cobra EVER again, and I will pay you 50 potions to take it out. Do something except what you are doing, please!