As an avid fan of all GW titles I too was looking forward to this first and only expansion. Again, as in previous titles, I wasn't dissapointed although a few things annoyed me. Let me first tell you the fun stuff: As this is 'only' an expansion, it starts where Prophecies stops (sort of); this way you can pick up the storyline, which in my opinion was the best of the three titles. Once you get a bit further in the game, you begin to unlock certain items/NPC's/skills, some of which are awesome. You can also prepare your current characters for eternal glory with the 'hall of heroes', here your characters will be displayed with their armor, weapons...etc for all to admire once we all begin on GW2.
For the rest, the gameplay hasn't changed, the looks haven't changed. No need to, as this was more than OK.
The frustrations: certain services/kits are no longer location bound or bought with money. You have to earn titles before you can do this or that. That's OK to a certain level, as it avoids the classic situation where a new player is 'run' or 'taxied' to a more advanced area, gets all the benefits from this area and then goes back to finish his early quests.
Also, as stated by others, I feel it's just a filler until we can lay our hands on GW2.
Nonetheless, the pros outdo the cons so my advise is: buy it, enjoy it and lets meet in GW2!.