I agree that this is annoying. But as was witnessed during the Nocturne preview week, where updates happened twice a day, it is possibly more annoying when you can't see certain Kingdom cards because your client doesn't know about them.
There should be a grace period of say 1 hour, during which you should be able to finish your game, even if you have to reconnect for whatever reasons. I have no idea how hard this will be a to do, and since updates regularly happen not that often, it may not be high priority.