What can I say? For me and quite a few others the biggest loss would be their contests. They have the best & fastest online reporting of the results and they also have links available so you can print out your own certificates. I just received my certificate for the 2012 Ten Meter contest from the ARRL last week. The ARRL could learn something from them about how to handle the afterwork when it comes to their contests.
I think the CQ contests will remain in good hands regardless. The contests are managed (and certificate mailing/postage) by volunteers. See http://wwrof.org/
ARRL historically has been excellent in quick turn-around of certificates. The recent breakdown was due to some issues in their radiosport section - which are being addressed quickly. I would expect them to get caught up and back to normal soon.
73, Dave KH2/N2NL