Actually I am not stuck in any mindset of proccing but it is clear to me the different possibilities.
1. Every ability present can be a proc, and it will only be 1 of them at a time, this is the view I was operating with.
2. Every ability present can be a proc, and it has a chance to proc with any of them.
The thing is I am now seeing it must be closer to your take on it than mine as apparently solo NIN/WAR using voke isnt always proccing ja, and if the only options are the ones present, it would never fluctuate away from it. However you can see why my opinion was that if you are only having one possible ja ws or magic spell work out of all present, minimizing the number present is important.
If this is how it works then it kind of sucks b/c I can see people spamming stun ws if they have it or w/e low damage shit ws trying to proc ws mobs.