Broadswords and Gladius are still both by any and all accounts you will find, Swords. So your comparison is flawed slightly. Yes there are some Knives longer than others, some daggers smaller, but the real difference between Knife and Dagger is a Dagger is a double sided weapon and a Knife has only one serrated edge. But to keep with the topic at hand, the Khanjar are very large in all senses of the word. Length and Width.
The Khanjars in XIV is about 1/2 the size of my entire Mithran body. their size contradicts the NIN and ROG job/class in general... You're not throwing around a weapon that big with speed and precision, and thats the entire concept of the job lore wise. The entire feel of a rogue-like class is their nimble actions, which is only possibly because they don't use ridiculously oversized and heavy weapons.
As for "Who says NINs [strike]go from 1-10[/strike] only wield daggers?", well, apart from digging around cutscenes for far to many hours knowing full well even if I found proof you wouldn't believe it or change your mind so I'm not wasting my time... the best I got is the jobs lore from release/lodestone...
I see nothing in that saying "Pride themselves on wielding large bulky weapons to slow themselves down" or "Short Swords and Cutlasses" or anything of the sort. you can say something like "Long Knives", but for that sake of argument, I direct you here: http://en.wikipedia.org/wiki/Knife There's nothing about Knives being half the size of a human body like these weapons are. Knives and Daggers do vary in size but I've never seen a Knife half the size of an adult, at that point its a sword of some sort.These agile fighters pride themselves on their skills with knives and daggers to make quick work of enemies.
I like variety in weapons, Hell I love the Khanjars because I've enjoyed their model since XI, but they are just a bit on the silly side. Its not like I'm demanded they be resized, but I have to acknowledge that they are huge like xbox.
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Most of the Golden Saucer glamour weapons are from XIGods damn it, I was wondering why the Khanjars looked familiar.
The bow is "Lamian Kaman"
the WHM Staff is the Staff wielded by certain NM Lamia in XI
the BLM Staff is the Soulflayer staff
the Polearm is the Mamool Ja spear (the one in Wanderer's Palace uses it too)
the Daggers are the Jambiya we're discussing
Blood Sword share a name and similar design to an XI weapon. I don't think the hand-2-hand has anything to do with XI, and the Shield is Odin's.