Under the description of the Discipline skill it reads:

Discipline plays a key role in the development of force abilities. See Chapter VIII: The Force for the full explanation.

So, away I flip...only to find there is no explanation as to why this skill is important to force abilities; in fact, the only reference at all in the chapter I can find is in regards to one of the upgrades to the Move power.

So, I borrow my friend's copy of EotE only to find the same reference in its description of Discipline. Subsequently, within its chapter on the Force,we find the same mention in the Move upgrade and also now an upgrade for the Influence power that uses it.

Is this really all the discipline skill does (currently) in regards to the force? I have to imagine this has been already observed and discussed, but I can't find any mention in any FAQ or errata and the forum search function is bringing up nil for me... Help?

That's all right now, of course we won't know what else it is used for until force and destiny comes out. In addition move and influence are probably the two most iconic Jedi powers. I don't think that it's a coincidence that it is used in a discipline versus discipline check for influence. I think that might be giving some idea of what direction they will be going in force and destiny.

I supose that simply refers to each power Discipline mechanics that uses it. Each power that uses Discipline has an almost clear description of it.

Could be for the same reason Green Lantern's ring requires the Will of the wearer to indicate how powerful it is.

Wasn't there a scene in the Samurai Jack version of Star Wars Clone Wars where this is touched upon?

The sequence where a padawan is assembling her lightsaber where it sounds almost as if building their own lightsaber involves imbuing it with a part of themselves to insure its built properly if i recall that properly.

Discipline might have a hand in explaining their way of handling the light and darkside of the Force but thats just me speculating.

Discipline matters in a mechanical sense for the Move power, as you need to make a Discipline check along with the Force Power check if you want to attack someone with a hurled object, difficulty being based on the object's size but otherwise treated as a ranged attack. In EotE there's the Influence power, and in order to affect a person's thoughts (aka Jedi Mind Trick), you need to win an opposed Discipline vs. Discipline roll against the target.

Discipline is also handy to resist various social skills, such as Coercion and Deception, allowing the character to keep a level head and not be unduly influenced by others. It's also good for Fear checks, given how often fear is listed as one of the paths to the dark side.

Come Force and Destiny we'll probably see more ways that Discipline is useful for a Force user, probably tied to other Force-based effects. One such thing may be a "Rebuke" type of effect (my guess is a separate power, but could be a talent or could be a default ability for all Force users) to defend against hostile Force powers.

And use of the Dark Side incurs strain, which can be recovered with a Discipline check at the end of the encounter. Not exactly the same thing, but relevant.