Now, I'm not saying the following because I'm a PLD, but because it was something that I found a bit weird when replaying that scene while being on another job and I think that it can add to the discussion:
In the scene after the fight with Lahabrea at the end of Praetorium, when we get teleported with him to the void, we hear Hydaelyn telling us something like "If thou would pierce the shadows, make thy a blade of light". Now, in that context, a blade would usually be a sword, and there's just a single class/job that can use them currently. Not to mention that while I was on that other job I found the slash animation a bit out of place.
However, I think that that might just be an oversight. As far as I'm concerned, each class/job has its own reasons to be considered "the most relevant".