Well, a new player coming in will not be able to share the experience that we had such as the Battle for Lion's Arch, but remember there's 250 years between GW1 and GW2 and there's a lot that happened in that 250 years that none of us saw. We came into the game seeing Orr in a state of destruction, very similar to how a new player will see the current Lion's Arch. It won't be important to them that they missed it.
But a new player will not feel any kind of shortage of content to play, the game launched with a massive world and an incredible amount of content and they have added a lot of permanent content since the game launched outside of the Living Story. I've got thousands of hours into this game so far and I haven't exhausted all the content yet.