Dear developers, I like the game but is more like a lottery with these cards rather than a game that the most skilled and clever player can win.
Everyone can win if he always takes so many soldiers from the cards. For example, at my last game there was a beginner player that took at his first attempts 12-12-10 soldiers at cards and I took only 4-6. Of course he won, although he didn't know the basics and this is a very frustrating experience for a good player.
So my suggestion for you is to find ways to make the game more fair and more rewarding and satisfying for the good players and not for the lucky ones. Give less troops at cards or give them less frequently or anything else.
You can play progressive and cards will be a lot less luck based! It becomes more strategy and based on when you trade cards instead of what cards you trade :)