I didn't get that from the interview. The way I understood it was that there would be a possible 1 month gap between end of 1.23 and the start of 2.0 beta in order to move over all character data. I don't think they would make people start new characters for the beta after moving their data over... They need to make sure everything went through smoothly so it'll benefit them to let players log into their accounts and make sure everything is intact. Which is why I think you'll be able to log into your own character for beta.
Then again I could be wrong.
Edit: Add to this the fact that beta will be about 4 months and you'll be able to remake your character (race/features/etc) while keeping your stats.