I will try to keep this short, but I am also convinced that this is how it might work as well.
Let us say Sakura's Substitution Jutsu for example.
It is Ninjutsu.
It is a Defensive skill.

That being said, we know that Resistance has a significant effect to reduce Ninjutsu damage. So ideally this should more or less be what increases the activation rate.
However, I still think that Ninjutsu itself plays just as much of a role in this.

The same can now be said about Neji's rotation.
It is Taijutsu.
It is a Defensive skill.

So I'd like to believe that Defense would take priority here and then Attack after.

Now I don't have actual proof to back this up, but I am basing this on the idea of simple logic.
Perhaps if a Mod could ask the Devs about this and let us know, that would be great.

In any case, River Phoenix has the right idea for Mood choice. If anybody can verify the way Defensive skill activation rate works, that would be wonderful.

One last thing that comes to mind.. Is refinement progress. That could play a role in this as well.
So many unanswered questions. Hope we can get some information. This post was last edited by RakaMikazuki at 2016-9-8 16:16

Yes, I agree with you, but I think there really isn't any sort of reliable way to test.

Although, one step would be to empty all magatama from the ninja and try. Do roughly 10 battles of 10 rounds having an enemy attack Neji without magatama, and then another 10 battles of 10 rounds with them.

Though 100 total rounds is still a small sample size, I think we'd be able to at least notice any changes.

Regardless, this would make the game more interesting and give more sense of what you want a ninja to do. Though I got to ask, does Kimimaro block multiple times ever in a single round? I know Neji can.
(I think Kimimaro only blocks one attack.) This post was last edited by RakaMikazuki at 2016-9-8 15:53

Yeah, I figured as much. Thanks for confirming that for me.