If someone misses a turn and they're a new recruit then yeah they'll probably deadbeat. But people should assume that players with 20 odd completed games and high scores aren't deadbeats.
We are trying to promote people to take their turns, its more in the spirit of the game, and makes for a more fun game in general.
What's more fun about never being able to miss a day of checking your games without being severely punished? That's just destructive and causes a clash between real life priorities and CC priorities. We can't all always be online. Also the spirit of the site is that it's for casual players and "hardcore" players. We don't want to frighten away the "casuals".
And as for not joining games when you know you can't play, that doesn't work because:
1. Games sometimes last a lot longer than you think
2. Things come up that we have no control over.