Why a parachute-dropped torpedo would lose the Swordfish's advantage

Would a parachute-dropped torpedo, like those used in modern anti-submarine warfare, have helped the Swordfish at Taranto?

No clear advantage: it would require a faster, higher drop and give up the Swordfish's useful ability to approach and release very low and slowly.

The question compares a Swordfish attack with modern aircraft that release lightweight anti-submarine torpedoes under parachutes. A parachute system is useful when an aircraft is flying faster and higher and must slow the weapon before water entry. Taranto rewarded the Swordfish's ability to release its much heavier torpedo while flying very low and slowly. That profile helped the aircraft pass below the engagement envelope of some Italian anti-aircraft guns. Changing one part of a weapon system can remove an advantage created by the aircraft, weapon, and target environment working together.