I believe that it was Polybius, a Greek noble who was taken back to Rome as a hostage after the conquest of Greece and Macedonia, who observed that the Greeks were horrified at the damage done by the Romans and their gladii in the Macedoinan Wars. They found men gutted and such, of course, but they also found them with their arms, legs, and heads lopped off by the Roman gladii.
Roman troops were taught the same basic sword techniques as those gladiators such as the Myrmillos, who used the shortsword and the large shield. Those tacvtics stressed stabbing as that exposed the soldier to counterattacks less than raising his arm to trike a chopping blow. It also required rather less space in the close confines of the line of battle. The Roman legions would charge, pause at about 50 yards to throw their lighter javelins and theyn move forward to about 30 yards and throw their hevy javelins, the pila. These latter were so desiged to bend upon impact so that they could not be thrown back by the enemy. Their pur5pose was to pierce the shields of the enemy and, hopefully, to skewer the guy behind the shield. But the pilum would, at minimum, so encumber the sheld as to cause the man to discard it, making him meat on the table for the legionary who was now charging with his drawn sword. The legionaries would slam into the enemy line, using their huge shields as battering rams, to break the battle line or shield wall and to knock thier opponents off-balance. At that point, they would set about stabbing around or over their opponents' shields. if they could not do that, they woould go for the exposed arms or legs.
One advantage that the Romans had was that they used the chessboard battle formation which they called "Triplex Acies" and/or "Quincunx', whereby the tiring troops ion the line of battle could be pulled back and replaced by fresh troops without having a general retreat. It was a trivky maneuver requireing intensive training and practice, but they did it on many occasions.
For more current references on Roman military tactics, try Polybius, Josephus' The Jewish War, and Caius Julius Caesar's various commentaries on his campaigns. When reading Vegetius, you need to remember that he is writing in the 4th Century CE about Roman military organization in the 1st Centuries BCE & CE, and that much of what he writes is nostalgia for the "good old days." For a good modern discussion of the evolution of the Roman Army and its tactics from the early citizens' milita using a Greek style phalanx to the legionary tactics of the early and mid Principate to the Field Armies of the Late Empire, may I suggest adrian Goldsworthy's excellent book, The Complete Roman Army, John Warry's Warfare in the Classical World: An Illustrated Encyclopedia of Weapons, Warriors and Warfare in the Ancient Civilisations of Greece and Rome (Paperback), a bit dated by now, but still an excellent basic book, and Peter Connolly's excellent Greece and Rome at War.
