The game currently has a "kill" (piercing / explosive) role and a "support" role (everything else)
It would great to also have a defensive and an healing role.
The Tesla cannon looks perfect as a defensive tool.
You need to aim it at the general direction of incoming fire or it doesnt work (maybe it can create a 45degree magnetic shield of sorts).
It maybe should damage the engines, and if you try to fire more than one together, the magnetic field become unstable and both guns break.
Another defensive gun could be "air expansion device". You point it at an allied ship, or even at empty air. When it hits a friendly ship, or you use secondary fire, it creates a blast of air that moves every ship in range away from the blast point, allowing for disengage, but dealing no damage.
This could lead to a lot of grief, however.
The "healing" role would have a "nanobot projector" gun that repairs allied hull armor damage, enabling them to tank better.
Maybe an invulnerability gun. You shoot it at a friendly ship, the component hit becomes immune to all damage for 5 seconds.
The support role could be expanded by having "support structure" guns that don't fire, but each of those mounted will improve one aspect of the ship. For example, you could sacrifice one side of the galleon in order to put two "hull armor amplifiers" that each pasively give +15% maximum hull armor
For additional fun, remove the ability to see enemy loadouts at character selection.
You never know who is the tank in the game until you try to shoot at him.
The meta would change, as each ship would need to try and stay away from the tank who will to absorb your fire, while trying to kill the damage dealer without getting disabled by the disabler, or any other similar combination of advanced tactics.
Yeah, maybe i played too much eve online