three simple sugestions: the first one is a litle simple, just know the name of oponents deck after and during the game... like a title over his hand or something like that gives the game more personalized war stile (ex: KingPirux's lightning heros vs Anyyone's god's destroyers)
the second one is to show wins and loses on player's data screen (where hobbyes and email is shown)
and the last one is experience and lvl, or just lvl based on the player's wins and losses. just for fun it could be better an experience stile, bassed on victories of the opponent you win a certain quantity of experience and/or bassed on different player's battles (while more battles you are playing more experience you get when you won on each one, in this way you make new people search and play more) something like that... :P of course it is just for fun...
o! and it could be cool to have a button to delete all the messages on the messsage board... because i have more than a 100 and i dont want to go one by one deletting them or reading that i lost T.T ... or win ;)
ou i get a new one: game slots (for example: 20) could be nice (very nice)