SO, following the wiki's lucky title guide, http://gw.gamewikis.org/wiki/Luck_titles_guide
It would, on average take 724 hours to gain the highest tier of the title, and would cost some 2.206.000 gold (second table). The reward for it would be a 12% increase in chance to retain a lockpick.
Now, different chests have different chances to retain a lockpick, but the effect of the title is a constant 12%. So, if we were to estimate the monetary gain of the title, we could multiply the price of a lockpick by 12%, yielding a 180 gold saving per lockpick use.
By the saving, the money invested into getting the title would return by the time the 180 gold gains accumulate up to the 2.206.000 gold. That's 12255 lockpick uses. Take 5 chests per area (ideally), and you need to explore 2451 maps for that.
Worthwhile?
I've only played some 1600 hours of GW in the year I've had it, and it's already getting somewhat stale (best value game ever, but you can only eat so many steaks before you get full), so I'm not bothering
