Why was it so notable, well getting a fair warning from my less brave counterpart, this place is the best kind of place to explore. It consists of two floors that are connected via multiple doors, with some tricksy parts where some doors can lead to single rooms up above or down below and disconnected from the rest of that floor, rooms with multiple doors, that sort of thing. It's not too hard to figure out, what is hard is making sure you find all 23 places for the deed i.e. being 'thorough'. The simple strategy I used was to pick one floor and work my way around trying every door, then swap to the other floor and connect the dots and try to spot areas where a door hadn't been used, still the last 2 or 3 took a bit of retracing my footsteps to fully complete the deed.
That side-quest with its nifty title for a reward kept my attention for a lot longer than the actual quest, it perfectly suits my personality to explore every nook and cranny for something interesting but on balance the deed is catering more for an achiever than a true explorer who might find delight in spotting some attractive area but often there is little additional content or treasure for taking the time to explore everything that looks interesting, sometimes you might encounter a 'rare' mob because you are going off the beaten track where they are less likely to be killed.
I must admit if I wasn't playing my burglar I probably wouldn't have been so enthused for the actually deed, which is why I leaning towards making him my main for the expansion. My captain has been parked at the dwarven town in Forochel for weeks waiting patiently to enter the mines but I've been there before and know it to be crawling with dourhands, the combination of no stealth, slow killing, confusing passageways and multitudes of mobs is so unappealing I think he may be there for a few more weeks.
The exploration deeds in the game aren't particularly engaging, sometimes like in the Trollshaws where ruins are spread around canyons it can get tricky to work out how to get where you want to go. Secret deeds like climbing the two towers in Mirkwood or the fishing hole in Enedwaith (which I've still not found) are a little more interesting, but not quite up there with eating a piece of old cheese I found in the barrows. The seven swords deed in Angmar was good because there wasn't a quest for guidance, but finding some guys sitting on their own in random places about the landscape wasn't really fun, and then the rewards, a title that wasn't 'of the seven swords' and a 6-man instance that there isn't the slight possibility of getting a group for seeing as it was in East Angmar.The solution is in the game already, walking through the epic book instance you see ghostly scences but they don't give much info, unlike say the flashbacks featuring Gandalf beneath Dol Guldor, but what if they had a bit more drama to them to piece together into a narrative and give clues to where a secret cache might be hidden or how to find some concealed passageways. Something that could be missed if you are not paying enough attention and that need a bit of thought. There does seem to be some light on the horizon with plenty of accounts for GW2 of players going off the beaten track and finding all kinds of events, objects to interact with and not being led there by the nose. Likewise, The Secret World is looking like it will incorporate plenty of puzzling, the need to pay attention to surroundings and spotting clues, with some of the story being played out before the players eyes if they are actively observing. I tempted to give Rift another go, because I never got very far in beta and they seem at least to have things hidden off the beaten track.