The November 30 date is vital for the Obama Administration. If the Administration comes out on that date and says there is still work to be done to make the ACA website work adequately, then the shit hits the fan. If the November 30 date is missed, republicans will go fucking wild in their attempts to kill the ACA and at that point, anything WILL be on the table. So Milbank is on target if he is looking at that November 30 date with trepidation.
The Obama Administration largely brought this on itself. Yes, republicans were complete asses, but that was well known all the way. Republicans didn't provide funds for adequate rollout, but the Obama Administration had access to some discretionary funds that could have been used, republicans couldn't control that use. So the President is right, his Administration fucked up and it needs to fix the problem. If the Administration has a working fix in place on November 30, the game is over for republicans and they know that. If the Administration announces a fix on November 30, more people will visit the site at all hours of the day and night to view plans and sign up, my claim is that the overwhelming number of those people will like what they see. Nervousness by some Democrats now will help those people later if the ACA is working well when they face their republican opponent, because they can say that they pushed the Administration to fix ACA problems, but they still believed in the good that the ACA would do for consumers.