@eva1977
Honestly, I've never been a fan of TDM, but for other players who keep saying, "Hey, we can use this for TDM!" in every new Adventure or game mode or random event (or Tuesday), maybe if we can get something added to the sandbox they'll leave the rest of us in peace to do their own thing and not try and force it on every other pirate that wanders by (I'm thinking not too fondly of the "A Hunter's Cry" adventure debacle last year).
To that end, if we're workshopping ways to make this idea feasible why not use the existing skeleton fortress islands for that purpose?
Okay, so the Skeleton Fort and Fort of Fortune world events are two of five in the world event rotation at any given time, which means for the other 60% of a server's full lifetime all nine of the skeleton fortress islands in the game are sitting vacant and completely unused except for the random-odd pirate harvesting gunpowder kegs.
I only say we should use the skeleton fortress islands and not the haunted sea forts because the haunted sea forts are already inhabited by enemies at all times, contain treasure at all times and are all exactly identical layout-wise except for cosmetic differences, so you'd always be fighting the same fight and I would imagine it would be prohibitively more difficult for the developers to go in and figure out how to turn "off" and keep off the already programmed enemy and loot spawns. It should be much easier for the "random" generator that selects which fort turns into a SF/FoF Event to see one is already in use and skip to the next free one in the series. Skellie fortresses are almost always empty and are all drastically different layouts, making each battle unique each time.
If, like @BurnBacon mentioned, we're worried about overlap of Tall Tales or trading company voyages taking you to an island that someone's "fort" has been constructed on, there are nine fully built and most likely vacant islands already set-up for exactly that purpose. Even already have cannon emplacements installed! You can sink gold into adjusting defences (additional walls, doors, cannons, etc) like @EVA1977 recommended and run your own little TDM mini-world event against as many invading crews as you wish.
There are details that would need to be fine-tuned by development in regards to what is possible in-game using the engine and such, but it would be nice to get some more use out of the skellie fortress islands and keep the TDMers away from the rest of us "normal" people... 😉