If I have the Niman Technique talent, which lets me use Willpower in place of Brawn for the Lightsaber skill, does it also let me use Willpower for talents like Counterstrike from the Shien Expert spec? I am a little confused because it seems most Lightsaber techniques have to be taken before other talents in the same tree that specifically call for a Lightsaber check, except the Shien Expert, which lets you pick up Counterstrike without having Shien Technique. By RAW, I would say that no, taking Niman Technique does not allow me to use Counterstrike with Willpower, but I'd like clarification. Not sure what the intent of the rules was given the slightly inconsistent tree structure when it comes to Lightsaber techniques.

It doesn't. You specifically need to use the listed Characteristic for those types of Talents, and you also need to be able to have access to using that Characteristic. This means that if you took the right side route of Soresu Defender, you couldn't use Defensive Circle without being able to use Intellect, which means you need to actually grab Soresu Technique first.

Think of it like this on the narrative aspect. You can pick things up from other forms that can better your use of another form (Parry, Reflect, Makashi Duelist, Multiple Opponents) that can allow you to blend multiple forms together, but certain techniques (Hawk Bat Swoop, Disruptive Strike, etc.), are so unique that they can only be performed in a very specific manner.

Perfect, thanks!

Note that the structure of the Shien Expert tree is cleanly divided into two: the right side represents Shien, and the left Djem-So. Since Djem-So is more about strength, but derived from Shien, it makes sense that the Counterstrike talent is in a very "optional" placement as you progress through the tree.