I've run into an issue during my campaign that my Knight can't actually use the greatsword (or other two-handers) despite having the perk. I've read on the Steam forums that they seem capable of using it, so I don't know what the issue is.
Now I do have the Sword Cora, but I'd like to be able to leave Threver with the magic greatsword.

Also saddened the Knight can't use Hallows, which means you also lose that in Threver.