Looks like they updated the page for the razing and you can tell what some new wvw abilities are:)
https://www.guildwars2.com/en/the-game/releases/march-2013/
Looks like they are also changing the way the mega boss chests work as cited here:
https://forum-en.guildwars2.com/forum/info/news/Upcoming-mega-boss-chest-change/first#post1656442
its going to be once per day per account for rares but you can still get chests on every character.
» Edited on: 2013-03-22 08:10:56