Here is my wish list of interface tweaks:
• When importing a deck list, if an upgraded card is listed which I do not have but I do have an unupgraded version of that card, put the unupgraded into the deck. (This could also be a user option.) If I am testing a fully upgraded deck in the trainer, it would be nice to be able to import the list into my regular account and have some version of all the cards present, and upgrade as I grind without needing to constantly update the list and/or hunt for the missing unupgraded cards in my list.
• Import / export Marks along with the deck list
• For people who came on board via Kongregate, offer a means of changing the password to something I can remember rather than having to copy/paste the random string of characters every time I log in to the full version
• On the Oracle, don't spin a Nymph and then tell the user he doesn't get it. That's just mean.
(I would rather not see the nymph at all!)
• More seriously, when the user wins a card via the Oracle, one single click to exit the screen, rather than click to get the card and click again to exit.
• Heck, it wouldn't hurt my feelings to see the user always get the card the oracle picks, with two buttons shown: exit and sell the card, or exit and keep the card. (Naturally, for rares it should show a warning before selling. Also, this should mean the oracle no longer gives electrum. You just get a card, which you have the option of selling immediately or keeping in your regular collection.)
• When a player can do enough damage to kill the opponent, turn the health bar red instead of all yellow. (Often when the damage is one point shy the green is either a single nigh-invisible pixel, or just plain absent.)
• Put in a setting (for each user) where the user can choose to have it automatically spin all available times after a win.
Please note that none of these have anything to do with mechanics - just minor tweaks to make the overall experience a little smoother, and to cut out some extraneous clicks.