well the problem w/ Torpedo Sphere is this, too much Fire Power, which is funny , since all that Fire power would be wasted in micro...
If implemented it would be OP, as it would be able to break any capital ship shield very fast, leaving anything to a SSD or a fleet to eat
Also they were not very common, and there was probably less Torpedos Spheres than Executor SSD
Yet its a massive Warship that could destroy an entire fleet:
http://starwars.wikia.com/wiki/Battle_of_Tralus_(Galactic_Civil_War)