1. Change marked history from "player search" to "card search"
So it is way easier to find the cards you search, since actually I we always have to click page by page until we found that card.
2. Change the titles from the avatar card from "release date" to "A-Z".
So it is way easier to find the title, you want to wear.
3. Give the possibility to change the appearence of a cards artwork from all level, the player got. Since often level 3 ist important to have, bacause of skills and stats, but most tim Lv 2 or even lv 1 looks way cooler, cuter or more beautiful, than lv 3. Many player think this. To avoid misstakes from opponents this could be an optic change only for the player himself to see. But this would upgrade the fun factor of the game, we want to see the great artwork.
4. Make loads for all cards and in the normal room show them to the opponent. So newbies can loacet killerdecks before starting a game and fair games would be easier to find.