That sounds like a great idea to me; replays auto-delete unless you save them, and you can only have a limited number of saved games.
Thanks Draino for supporting the idea. The current state of things is, the last 20 games you played are recorded (including time-outs before bidding), and are overwritten with new ones; it's a matter of overwriting.
Perhaps 10 "saved game slots" are enough for the average player, but that can be a bit short for those addicted to build new brainy engines. Do you know anyone?

Please everyone else, join the talk!
On a related issue, I think we need to be able to delete stats for specific decks. I've got a huge number of stats for decks that dont even exist anymore, but right now there's no way to get rid of that useless data.
Man, you speak the truth! Like Dictionary says, sometimes I just change a dot or a misspelling in the title of a deck, and that little change means more useless data will be gathered as a separate new deck. That needs to be fixed; is not useful by itself and reduces the usefulness of the other data.
So with Dictionary, Sgtdraino and me, there are 3 votes. As long as democracy means something (or provides some help)...