Just to add, in regards to which sword would be associated with which Archangel, should they actually be sponsoring one in a passive way.
“Whatever you do, do it for love." - Uriel
As Gruff said, Sanya got Esperacchius (Hope) from Michael
AA. It seems likely that it was Gabriel trumpeting loudly through Murphy in CHANGES when she briefly wielded Fidelacchius (Faith). And Michael seemed to be on a first name basis with Uriel in SKIN GAME, having previously wielded Amoracchius (Love). Seems like a good chance each takes a vested interest in what their sword, and its bearer, is doing.
Also, If Raphael did have a pre-crucifixion Holy Sword, but was otherwise engaged in bartending due to having given up his Grace, then it would explain how the sword could have ended up unmade.
No need for Merlin to step in and stop a death blow. If the sword was used against an innocent, it would lose its connection to its sponsor, and leave it vulnerable. Any number of things could have happened to then leave it shattered and broken, just like Fidelacchius. And with no Jedi faith to encourage another's belief in the broken blade, and no active archangel to oversee its fate, it fell to the wayside of history.