One problem. Certain bosses like Anga gain resistance to attacks that are used repeatedly, and future content will introduce enemies that gain complete immunity to the weapon that was most used on, this in turn WILL require you to have multiple weapons equipped at all times. So in the end Pure weapon builds are useless in future endgame content. Just a reminder from a former pure katana main on JP version.
I figured Anga built resistance, but my question would be is the resistance per original user or does this affect all users.