Since the announcement of this month's event, I've started to speculate what the next possible update to the Caribbean could be.
From the sounds of this "mystery weapon", we're probably gonna be seeing new loot drops in the form of stuff on our Unreleased Items page. And the star of this update will probably be the legendary weapon, The Heart of Padres Del Fuego.
Releasing the unreleased weapons into loot would be a quick and easy way to jumpstart POTCO again. The content is all ready for release, all they need to do is have it up on test for a few weeks, then send it live. No development costs at all. Of course I'm not saying they should be spending more money on the game. I just think this would be a natural and quick choice to get back in the swing of things.
Of course, this "Mystery Weapon" could just be another redeem code, but they don't always call redeem code weapons "an undiscovered weapon of power".