At the moment with only 10 cards in a deck almost all the advanced players have the deck made only of gold cards, sometimes a legendary one and few silver ones, you will never use a common card. This for me is a waste of your work, because the majority of the cards are common cards and they are never used if not at the beginning of the game, when you don’t have enough gold,silver and legendary cards.
I wanted to post this suggestion to the dedicated topic but I decided to post it there to get the feedback of the other players.
The deck should be bigger and as the legendary cards the gold and silver cards should be limited. For example the deck can have at most 15% of gold cards and 30% of silver cards and the rest 55% must be common cards. So in a deck of 20 cards you can have at most 3 gold cards, 6 silver cards and the rest 11 cards must be common cards, legend cards should be considered as common cards in the calculation.
A bigger deck will make the game a pure luck game! Yes because already with 10 cards the most efficient technique is to destroy faster as possible the first adversary assault units, when you have an advantage of 2 units on the adversary you can consider to have won the fight. So with a bigger deck with few gold cards, the first one, who get them will most probably win the fight. For this reason also the game play should be changed, I think a player should have the possibility to put their assault units in defense mode, this means they can’t attack but they receive the half of the damage and all the skills have the half of their probability to trigger.
This would have a big impact on the whole game, which most probably will be never changed. So at the end the best solution is to design only gold and silver cards and leave the game as it is.