Leondres: I'm guessing here, but it seems that they didn't realize how big of a game this was going to be thus their servers couldn't handle the load.
The official explanation would be:
As for the midnight update - it's always a difficult decision to put servers down as there is always some risk involved. The current infrastructure consists of over 16 core machines and two external datacenters. We work on master machine which propagates the changes to slaver machines and to external datacenters. This takes some time, especially that the DLC and the registration clusters have a lot of encoded files. Today we also had to decode and encode all of those files for the move and this took most of the time.
As for the forums, they are rebuilding the whole thing to accomodate the new amount of traffic, add options people requested on the old forums, and get up to date with the internetz in general.
I personally think they're understaffed. They're a medium sized Central European dev company, releasing an AAA title, things were sure to get SNAFU to some extend. The office must have looked like Apollo 13 Command Centre on launch night.
Considering all they're doing pretty well. Not perfect, but very brave and determined >.<