I can't see any harm in filling out the form manually and mailing it in... (like we've been doing for many many years)! BUT... on the other hand, if you decide not to file anything and just wait until the system comes back online, well, as others said I think there's some potential risk for you. And the printable PDF 3-186a form on the Federal website is the approved format and contains the same information as the web version, I can't quite go along with an argument not to use that because of some state specific language around the process of using the new web/online system.