Just a suggestion but could me legalize the use of upped cards if the two people agree on if and how many. Because some of us have upped decks that we like and use regularly but just haven't ground enough, or just aren't winning constantly enough to make it into the challengers league.
Yes, this was suggested at some point in chat, but the problem with it is that it's too easy to cheat.
Lets say we agree on using 6 upgraded cards. I could easily take 9 and just not play the other 3. There would be no way of you knowing how many I had. And even if you saw me play 12 upraded cards, there's no way of proving that unless 7+ cards are visible at the same time.
Having some kind of game log that shows all the moves made would help fix this problem. Well, at least the second part of it.
That being said.. I guess if you trust the other person and you both have the same amount of upgraded cards, I see no problem in making custom rules for that individual match.EDIT: Scratch that. After talking to people in chat and getting their take on this, I'm pretty convinced that it's better to just keep it simple and have unupped matches only. There will be less cheating and other problems that way.