...is YC open to reverting to the current system if/when it doesn't work out?
Basically, it turns the system on its head; it's no longer "Bad posts will be removed," it's "Your posts will automatically be removed unless someone decides that they are good."
I'm actually really optimistic about this change; it will force people to be more civil if they actually want to participate. However, it will only work if lots of people are willing to put in the effort of endorsing quality posts.