Late Roman soldier not inferior to early legionary

[guy]

This is a good video that challenges the belief that the early legionary was vastly superior to the late Roman soldier:

 

[caldrail]

Sebastianus, observing the indolence and effeminacy both of the tribunes and soldiers, and that all they had been taught was only how to fly, and to have desires more suitable to women than to men, requested no more than two thousand men of his own choice. He well knew the difficulty of commanding a multitude of ill-disciplined dissolute men, and that a small number might more easily be reclaimed from their effeminacy; and, moreover, that it was better to risk a few than all. By these arguments having prevailed upon the emperor, he obtained his desire. He selected, not such as had been trained to cowardice and accustomed to flight, but strong and active men who had lately been taken into the army, and who appeared to him, who was able to judge of men, to be capable of any service. He immediately made trial of each of them, and obviated their defects by continual exercise; bestowing commendations and rewards on all who were obedient, but appearing severe and inexorable to those who neglected their duty. - Nea Historia (Zosimus)

So by long unfamiliarity with fighting the Roman soldier was reduced to a cowardly condition. For as to all the arts of life, so especially to the business of war, is sloth fatal. It is of the greatest importance for soldiers to experience the ups and downs of fortune, and to take strenuous exercise in the open. The most demoralised of all, however, were the Syrian soldiers, mutinous, disobedient,seldom with their units, straying in front of their prescribed posts, roving about like scouts, tipsy from one noon to the next, unused to carrying even their arms. -  Letter to Lucius Verus (Fronto)

Causes of the Decay of the Legion - The name of the legion remains indeed to this day in our armies, but its strength and substance are gone, since by the neglect of our predecessors, honours and preferments, which were formerly the recompenses of merit and long services, were to be attained only by interest and favour. Care is no longer taken to replace the soldiers, who after serving their full time, have received their discharges. The vacancies continually happening by sickness, discharges, desertion and various other casualties, if not supplied every year or even every month, must in time disable the most numerous army. Another cause of the weakness of our legions is that in them the soldiers find the duty hard, the arms heavy, the rewards distant and the discipline severe. To avoid these inconveniences, the young men enlist in the auxiliaries, where the service is less laborious and they have reason to expect more speedy recompenses. -  De Re Militaris (Vegetius)

Now in the place of Valens, his uncle, the Emperor Gratian established Theodosius the Spaniard in the Eastern Empire. Military discipline was soon restored to a high level, and the Goth, perceiving that the cowardice and sloth of former princes was ended, became afraid. For the Emperor was famed alike for his acuteness and discretion. By stern commands and by generosity and kindness he encouraged a demoralized army to deeds of daring. -  Res Gaetica (Jordanes)

Dr Adrian Goldsworthy has commented on the strengths of the late Roman soldiery, regarding their ability in 'low level warfare' (raids and ambushes) but the skills of large set=-piece battles had withered along with the Centurionate.