I’ve got an idea how you guys could safely start dipping your toes into the user generated content world for guild wars 2.
The idea would be that you could have your own Asura lab. You would collect different parts (ideas could include pistons, fire starters, tesla coils, simple circuitry as in minecraft, etc) and that these parts could be put into a box which would have multiple slots. The overall effect that the device would have would be dependent on the parts and the order that they were arranged within it. This could also effect the look of it.
This device could then be set up and used both in PvE or WvWvW (similar to how some engineer weapons are)
Therefore you would have a user generated weapon, the effectiveness could be controlled by the developers and it could be incorperated into the current lore.