User blog comment:B214/Talk About What You Want! 2/@comment-24409634-20140628103520/@comment-73.178.133.185-20140630224036

Wow, quite the argument here....

Alright, the Holy Swords Collbrande/Caliburn, Excalibur, Durandal and Ascalon were made by God just as the five Demonic Swords currently in the possession of Yuuto were made by the Four Great Satans. Other swords are made through other means. Excalibur's fragments were able to be reforged as seven separate swords at least in part because it was impossible to reforge the original sword as made by God. They were added to Durandal as a form of "control device" by Heaven (I'd have to go back and reread, but there was no mention that this was carried out by alchemists, just that it occurred in Heaven).

In other words, others can work with the fragments of one of God's Holy Swords and otherwise possibly "enhance" one of His swords but not recreate them.

As for the original topic, I have to agree with the general idea that Issei's "use" of Ascalon has been disappointing. It really feels like he should have learned how to actually wield the sword. But at the same time, it fits his characterization that he simply lacks the ability to learn proper martial arts, including kenjutsu/swordsmanship.