Sword of Spirit
Legend
If you weren't proficient in a weapon, why didn't you ever get proficiency if you've been using it so much?
Because no one in D&D ever uses a weapon they aren't proficient in, except for an occasional critical moment (only a strike from the Sword of Stuffage can kill the Badgui, and the proficient party members are all out for the count).
This isn't really addressing anything you said, just an observation that players don't actually use weapons they aren't proficient in, so it doesn't tend to matter.