Y'all need to be careful with what y'all call what.

In FFXIV weapons define Classes (Armory System). Akihiko Matsui gave no indication that such definition would change.

Unfortunately, he also didn't state how FFXIV will define Jobs (Job System).

Though they are connected, the two system are not the same thing and a definition or mechanic in one system does not automatically carry over into the other system. So even though the weapon a player is currently wielding means a lot in the Armory System, it may turn out that it means less than nothing in the Job System. It would be an assumption to say that it will, since Akihiko Matsui didn't say either way.