It would be great to get something, but I think they are putting a lot of effort into making the next main story expansion. If I recall correctly, areas like the Waterworks came out as filler between content expansions.
I'm pretty sure we may get an optional, challenging Dungeon for high-level Pirates in the game someday soon. Don't worry. We just request Kingsisle for it, and they'll make it happen. Sure hope it includes a new, tough Companion with it for the Crew, as an actual quest reward!
I would love some things like that I could do with friends. Pirates is a very solo player game (don't get me wrong I love Solo things. I had to quit wizards because it just got to hard; and lets just say I don't like going in with other people socially).
Every single task in wizards I needed friends. Ugh. But yes as long as the game keeps being solo I would like one or two places to try for rare gear with other people. :D