Sometime I feel like upgrade laks balance. I mean some cards are way more powerfull upgraded, think of desintegration, the cost is devided by 2, allowing you to cast it for only won single quantum which you can obtain at the second turn, even from a lonely mark. On the other sides, some unupgraded are nearly better than the upgraded one. Think of the red dragon, wich have lowered defense, increaded cost, for only 3 more atk. Or even bigger hope. Have you ever seen an upgraded hope?
Am I the only one to think that way? Thinking that upgrading some cards is thousand times a best investissement that upgrading some other?
Then, saying there is something that might be wrong without suggesting something to improve it, let think about this point.
Maybe the best thing to do is a listing of every useless or more powerfull than usual upgrade.