More beta events means that we gonna wait longer for Open beta and release, I hope they gonna raise lvl cap and unlock other locations in every closed beta event so we wont get bored ;)
All the places selling pre-orders which have a date are quoting March 1st, so that's what I'm assuming the release date is going to be. At their current rate of 1 beta event every 2 weeks that works out to 4 events between now and March 1st, which matches the current rumors/reports from in-game announcements.
That said, there is no reason that the last "beta event" couldn't be a week (or 2 week) long open beta. I'm definitely expecting that at least one or more of the later beta events is going to be longer than just a weekend so they can test server stability a bit more.