While majority a content patch, tomorrow will see some new internal mechanics/instance and systems added. One of the surprising bits of news is that a WvW based Legendary Trinket (ring) will be available. PVP game mode gets a Legendary Amulet.

Events scheduled after March 17th

There is another big (well, not so many words but BIG if you follow Guild Wars at all) announcement on the GuildWars2.com Blog