Fresh classes.

[Nahara]

1) Katana / Great Katana isn't something you should assign to Ninja and Samurai. Ninja would be ninja knife/dagger/short sword whereas Samurai is just straight katana. Great Katana is an odd weapon which I believe shouldn't exist ever and left with the more ridiculous type jobs (ie Dark Knight) for that "cool" factor.

"Great" was simply the prefix used in XI to differentiate between the one and two-handed variants of different weapon types. Greatsword vs Sword, Greataxe vs Axe, you get the idea.

Great Katanas were the two-handed weapons used by SAM and modeled after the real life katana, while the Katanas were the one-handed weapons used by NIN and modeled after weapons like the wakizashi.

[Kitru]

Great Katanas were the two-handed weapons used by SAM and modeled after the real life katana, while the Katanas were the one-handed weapons used by NIN and modeled after weapons like the wakizashi.

Actually, Ninja used the Ninja-to. It had a shorter straight blade compared to the wakizashi's curved blade, which allowed for the scabbard to be used for other purposes (a curved scabbard is actually pretty weak thanks to physics). Wakizashi was specifically the small sword of the Samurai daisho (lit. "big-small"; the pairing of katana and wakizashi that were the trademark equipage of the Samurai to such an extent that wearing either when you were not of the caste was a capital offense). Calling it a katana is like calling an English longsword a scimitar.

It's for this exact reason why you actually end up seeing the ninja weapons called "Ninja Blade" instead of some variant of "katana" in FF games with both Ninja and Samurai (in those games with just Ninja, Ninja use katana because there's no need to distinguish between the specialist swords of the two class/jobs). If both NIN and SAM are added, NIN should use daggers and/or ninja blades, which is what they have historically used in the FF series for those games with both SAM and NIN, and SAM should just use straight-up katana (likely just a single one in a 2h grip because, in the FF series, dual wielding has been the providence of ninja).

Also, random note, the larger "katana" designed to be used only in 2 hands as opposed to the hand-and-a-half (one or two handed) design of the katana were actually nodachi (lit. "great sword"). There was no such thing as a daikatana or great katana because katana referred specifically to the large portion of the daisho.

The problem with Ninja and Samurai both coming from the same class, however, is what Exstal already paraphrased from my points on previous discussions (which he seems fond of doing, given his signature): a Ninja and a Samurai fight in completely different ways, to such an extent that any job change would require such monumental changes to the base class that it would require as much work as simply making a new class entirely (new animations, new attacks, modified CDs, etc.). The only link between the two is the asian theme, which is not enough to have them stem from the same job.