Yup well said.
I think they would need to add quite a lot of depth (that does not mean complexity) to the job system instead of adding more weapon classes with a light job system, because right now we tend to say things like "Bard/Pug" because of FFXI reference, but it would actually be a bard that fights with knuckles who can basically equip any ability he wants with mild penalties. So keeping the main emphasis on the armoury/class system would not offer as much potential for deeper class mechanics, as you said, as building a strong job system.
I still think new weapon classes should appear in future expansions, but emphasis should be put on jobs for further character development.