I like the expansion as it has been described. I feel that the PvP and WvW enhancements alone will add an exciting and worthwhile level of complexity that I have been wishing for; "not to mention* the rest of the new layers. I have to say I am pleasantly surprised by the scope of the upgrade. The mastery system is intriguing to say the least. I will definitely play the new profession and look forward to the upgrade.
Guild Wars 2 has the graphics, the sound, the builds, the fighting action, the world.. but its launch could only offer a basic layer of complexity. The kinks are mostly all solved. Adding strategy elements that fit well with the existing landscape and engineering a richer and more complex fighting environment is going to hold my interest and, I predict, bring many many new players to the game.
Looking forward!!