Limiting the number of certain cards in a deck would help. It is the best way I can think to revive the competition of other decks and strategies that can be vaguely found but are too weak for a player to bother.
MiltosS comments below are absolutely correct. Unfortunately a 90% of the cards of the game are unplayable. Even a lot of promo are not playable because there are a couple of cards in the game that really ruin it. Wisp and butcher are the most illustrative examples. You see decks with 3 or 4 of each very commonly in the game and since you can't intervene in the game there is not a way to handle them. Unless you have the same cards, which makes the outcome of the battle pure luck. In addition the variety of decks you face is extremely limited as a consequence of the lack of other playable cards. If you spend some time in the chat you will see many players claiming that whole colours are practically useless e.g. the green on top lvl. this is true. I have all the promo green cards and still my green decks have no chance against a typical butcher/wisp deck. It shouldn't be like that. The game desperately needs BALANCE and VARIETY.
I ve playing the game for more than a month now and I like the game. Adding ounches at the everyday rewards was also a big plus because it gives the players who can't pay for any reason a chance to get professional set cards.
Laboratory is a good idea but: a) after completing the research you end up with thousands of useless experience points that is somehow frostrating b) it would be nice if every player had different (but equally powerful) cards to research because it would give more variety to the decks you have to face
Another thing is that the squads and cards option under the shop tab has very limited choice for the last 2 (usually most rare) cards. At the beginning I was eager to see what will be tha next ultra rare or promo card I would be able to buy, but now every time they are almost the same.
Finally a real time PvP mode against friends would be amazing. Maybe a small tournament option between friends with a reward for the winner
keep up the good work
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Thank you for your kind words and suggestions. We work to present something new soon. :-)