I think there should be a few things you can do before you start the match to allow 4 nicer duels. I'm tired of people asking for duels with me and then leaving because whoever's invested more has an impossible advantage. 3 options would be easy to implement like what's already in the arena, and'd make this nicer; changing your own health and or starting hand amount without cheating on the duel accept screen, with these set to default, and a button to reset these both there and on the options tab.
It could be fun for new players.