This is a very interesting thread, and I wanted to add some various material in old notes etc. as the subject of cut vs. thrust is one that has come up constantly in many studies of edged weapons. Probably the most prevalent discussions and controversies that record such discussions would be with British attention to this topic beginning in the latter 18th century in studies to find the ideal cavalry sword. Ironically these debates would continue into the 20th century.
Although detailed attention was directed to strategy, tactics etc. in most European armies, "...contemporary military manuals illustrate how little attention had been given to the actual use of the edged sidearm in combat situations for centuries" ("Secret History of the Sword" J.C.Amberger, 1996, p.31, referring to Prussian cavalry regulations c.1747).
In various observations reviewed in a number of resources, it seems that the thrust categorically won favor for its deadly effect, however it must be also noted that the slashing cut of the sabre in properly trained hands was most certainly effective. In fact, at Waterloo, Napoleon complained of the barbarous use of the huge M1796 British light cavalry sabres. Another narrative does qualify this somewhat, noting that "...it is worthy of remark that scarcely one Frenchman died of his wounds although dreadfully chopped, whereas 12 English dragoons were killed on the spot and others dangerously wounded by thrusts" ("Swords of the British Army", B.Robson, p.26, citing Capt. Bragge 3rd Dragoons, Peninsula, 1812).
In latter studies on cut vs, thrust, in 1913, then Lt. George Patton is noted in that "...his thesis was that the thrust with the point of a sword is deadlier than a blow from its edge. He cited Marshal Maurice de Saxe and Napoleon on the value of thrusting with the point". ("The Patton Mind" , Roger H.Nye, 1993, pp.33-34).
In "Sword, Lance and Bayonet" (Ffoulkes & Hopkinson, N.Y.1938, p.18) "...all authorities consider that thrusting with the sword is more effectual and that the wounds thus produced are more difficult to heal than those from a cut, and all agree that a thrusting sword is better for the cavalry". This taken from comments by Gen. Sir C. Beauchamp Walker, Journal of the Royal United Services Institution, Vo.XXXIII, 766. However, he comments further, "...though the use of the point is essential in the charge, it cannot be used in close quarters melee and that a man must cut his way out".
The next comments are key;
"...the main objection to the cutting weapon is that except in the case of the expert swordsman the tendancy in moments of excitement is to cut wildly, more often with the flat than the edge leading". (John Latham, "The Shape of Sword Blades", Ffoulkes op.cit. p.18).
Robson notes (p.34), "...very often the troopers were not well trained in the difficult art of mounted swordsmanship" (Cavalry Journal , III pp.470-4).
Therefore it would seem that the debate is actually more a question of dynamics vs. pathology and qualified use of both cut and thrust depending on situation. The thrust certainly would typically prove fatal, though not
necessarily instantaneously. In a study on this particular aspect in 1996, Frank Lurz, Military Master of Arms at San Jose State University noted that "...exsanguination is the principle mechanism of death caused by stabbing and incising wounds and death by this means is seldom instantaneous", and notes further that the combatant may continue for varying periods of time. This seems to make sense as in the stress of combat with massive adrenaline, and near frenzy , many thus wounded combatants have been known to continue fighting for even extended periods of time.
As I have noted , this controversy carried on for well over a century and as far as I know there was never really an empirically conducted 'study' that offered conclusive results. These references are but a few that occur in many resources concerning edged weapons, so to gather recorded data on this subject would be quite an undertaking. Hopefully these will illustrate the general consensus though.
Returning to the reference to the "old wristbreaker" :
This was a colloquial term for the U.S. cavalry M1840 sabre, which was not a thrusting sword, but a heavy sabre with a blade nearly 36" long. The origin for this term remains folklore, however probably came from the weight and poor balance of the sabre itself. These were patterned after the French M1822, which had been carried temporarily by the U.S. 1st Dragoons and swords based on them were ordered from a Solingen maker. During the war with Mexico in 1846, the complaints began that it was too heavy and no comparison to its French prototype. Whether the 'wristbreaker' term developed then or during its continued use in the Civil War is uncertain. The soldiers disliked these cumbersome, heavy sabres and frankly had no idea how to use them. As the Civil War developed, the sabres were dutifully carried and seldom ever used, but as John William Turner notes ("The Last Bright Blades" , 1982)..." it took time to train a good cavalryman in the use of the sabre from horseback, and there was not enough time".
On the difficulty with 'straight sabres'. I think this gets into rather generic application of a term and in the latter 18th century the officers single edge sword typically with knucklebow was termed a 'spadroon' and considered a straight sabre. The most common of these were the 'five ball hilt' examples of c.1780-1810. In most cases it seems the term sabre is often loosely applied much in the same sense as sa'if can apply to a straight broadsword or an Arabian sabre, which incidentally also often have straight single edged blades.
And that is my thrust on these matters