I really like the Djinn Chwala card, the only of the 3 that I have, but I don't play dragon really often in Bronze III so far, because I mostly only do my daily quests - or try to do them and get frustrated by loosing up to 10 games in a row, but yeah maybe I should try just to win a few games in between and as you wrote, thorns are a very mighty thing in Bronze - later on, no clue but never a bad thing to have them I guess.