I like the "I'm a crybaby who has quit X games" stat for profiles.
Of course I don't want to suggest the already overworked Kestas do more, but while I'm dreaming, the new game screen could have an option for blocking players from joining the new game who have quit more than X number of times.
Players who CD, could be charged double or triple the cost they initally paid to join the game, or be dropped straight back to 100, or even temporarily to 50 or less for a week or two for repeat offenders.
Not to suggest adding work for the mods either (though if done right this may acutally be less work) if someone has a legitimate IRL reason to CD, they can contact the mods prior to the CD to avoid the penalties, or possibly if an emergency causes the CD, then they could appeal after the fact. (Default, the mods could grant any request, since it takes some effort to contact the mods with an explanation of an IRL reason for the CD, and have a stat only the mods can see for each player for how many times they have requested a waiver of penalties for CD. Thus the mods can tell who is gaming the system with simple glance at their profile. A person who has a weekly crisis to get out of a game should be easy to spot).
As for how to address ruined games once CD's occur, I'm not sure there is an easy way to fix that. It's probably easier to discourage CD's in the first place.