I'm a stat freak. The more stats, the more happy I am. But I collect important stats to me anyway, so I'd at least like to see card counter.
IE. In manage your deck, I'd like to see count of total cards, count of upgraded cards, and count of each by element (when you filter by element). I believe this should be an easy, not very time consuming addition, that would be a big help to us who like to monitor our progress. Manually counting those every now and then is a huge chore.
I'd imagine that all "per deck" stats would require different approach of importing decks, or would require resetting, like what Beef wrote.
- TTW is a measure that says something only if you're winning like 90+% of the matches, which means its useful only against low level of AI, so I wouldnt put it as priority.
- Win rate per deck is definitely useful, and something people are already keeping stats from (if they care about it). EM rate included.
- Average time per game, while useful, its impossible to measure as you can stop in the middle of the game and finish it an hour later. Happens to me all the time
- Electrum won and lost per deck would definitely be helpful.
But yeah, I'm also more for further development of the game/cards etc.