Everything has already been told in the FAQ.
How about characters used during Beta?
The Nostalrius beta testers will NOT get their characters at server launch. We want the server to be launched like real retail vanilla servers used to be, where everybody has to start from level 1. The old beta characters could still be imported, but under several hard conditions. This importation should not alter the PvE or PvP progression, should not change the server economy balance, nor come with an sense of injustice from other players. We rather think that it could bring back a lot of old Nostalrius players (more than 20.000 accounts !).
Anyway, these characters will stay unusable a long time after the release (and their names will be reusable).
To sum up, all these conditions are here to ensure that
- these characters will not break the server balance (PvE, PvP, economy ...)
- the other players won't get any unfairness feeling
You should see these character importations as an opportunity to bring back to Nostalrius old vanilla players. But it is only an opportunity, not an obligation : we will not make importations if the new community does not agree with that.