Dalas120
What are Torpedoes?
There are guided and unguided versions of Torpedos (the unguided ones are faster and more powerful but don't travel as far), as there are guided and unguided versions of missiles, the unguided versions, of course, are known as rockets.
The true distinction between missiles and Torpedoes is the medium they travel in. Any missile that travels in water is called a Torpedo.
However a distinction that matters more in peoples mind is their effect, and the name Torpedo carries a bit fear with it. because they are that more destructive.
In the medium of space combat, it makes sense that there should be small fast missiles capable of tracking and killing small fast targets, and it makes sense that there should be larger versions for taking out the bigger targets too. As well as size and power, Torpedoes allow more sophisticated tracking and other devices.
Giving Missiles and Torpedoes distinctive roles and behaviours
If PD was altered, not to be less powerful, but instead to be harder to mount on small ships, then missiles could fill the role of small ship killer, and Torpedoes (with greater armour tracking and power) would be better suited for taking out big ships. Particularly if they are given the ability to bypass shields- which doesn't have to be OP if the cost and size of torpedoes is enough.