Since this question hasn't yet generated an answer, here's my guess:
There has been much discussion on the deficiencies of disarming technique against even an unskilled knife wielder, and swords are exponentially more dangerous, both for their range and versatility.
- Slapping away the attackers blade is the only defense I know of that has been proposed, and that was still considered dangerous even with a leather glove.
[See also: The History of the Rapier (2013)
Pure thrusting swords, such as late rapiers and poniards are so light and quick, a slap is unlikely to make contact. The blade can be thrust and withdrawn in a fraction of a second, the "sewing machine" technique can be utilized, and fencers can change the angle of attack, thrusting from almost any angle.
- The torso (typically abdomen to avoid bones) is a prime target, but a fencer can also stab at the face, legs, and even the arms, making defending one area of the body insufficient.
Cut and thrust blades, such as early rapiers, basket hilt claymores, and chinese jian, can additionally cut into a slap, which would be grievous, due to the amount of momentum that can be generated in a very short distance, and microscopic surface area in which the force is concentrated on contact.
Additionally, good fencers can put the point of rotation pretty much anywhere along the blade, such that even cut and thrust swords have a high probability of avoiding a slap.
- An expert knife fighter can kill with single thrust, but a merely competent fencer, if uncertain of those specific targets, can impale.
Generally, impaling is contraindicated as it can cause the fencer to lose control fo the blade, but in a one-on-one match, this is acceptable. Regardless, any puncture wound received from a sword anywhere on the body is likely to be non-trivial.
Post-medieval cut and thrust swords used for fencing are also quite capable of executing a "sewing machine technique".
- Advancing obliquely, as seen in in katana disarming techniques won't work, as fencers are quite capable of circling
Here the intent to to maximize the target area of the opponent's torso. While western sport fencing is entirely linear, free form fencing does not have such restrictions—in Chinese fencing, circling and changing direction is common.
- There is no way for an unarmed defender to disarm a competent fencer
The only strategy is to stay out of range.
[You can test whether this seems correct by simply by facing a fencer holding even an unwieldy wooden practice sword with a point, and evaluating whether that's a bet you want to take—here I don't even mean that the wooden sword is lethal, just that the amount of force which will be concentrated into a point is, in an of itself, strongly disincentivizing, and still quite dangerous.]