This is just one of the many promises that ArenaNet has made in regard to Guild Wars 2 as the studio strives to differentiate it from the rest of the fantasy pack. The interview covers the main features list of the game: the event system, the personal storyline, and the emphasis on exploration.
When pressed about in-game events and holidays, Flannum said that many Guild Wars holidays will be returning: "We haven't planned out exactly what we're doing yet, but we certainly plan to support all of our usual holiday events in Guild Wars 2. Since our event system is very robust I imagine we'll be able to do a lot more things than we were able to do in the first game."
He also said that the team is striving to "push the fun and collectability" of the mini-pets system over Guild Wars 2's predecessor. You can read the full interview at GamerZine.
[Update: Tap Repeatedly also has a whopper of a GW2 interview up today, this one with Jon Peters and Jonathan Sharp!]