First of all, there is the discrepancy between the release notes and the in game description, in the release notes it says "Highest of Enchantment or Illusion bonuses", but in game its says based on illusion, no mentioning for enchantment. That being said, my illusion and enchantment bonuses are the same, so I will ignore this for the purpose of this post.
It was already established that the low saves of the goblins in "a sharn welcome" are their "will" saves, and you can land will based spells consistently if your DC is in the high 60's on EE. my enchantment and illusion bonuses are 28, my charisma modifier is 31. so the DC should be 20+28+31=79.
Regardless of the mobs weak will saves, because this spell supposedly rolls 3 saves for each effect (so it rolls 1 of each will, fortitude and reflex), I would expect that at least 1 of the effects will land most of the times. So, I went to test it in "A sharn welcome" and rarely landed the spell. those goblins saved most of the time. Same with the other quest in part 1 sharn, mobs rolled saves on all 3 effects. Is there a known issue with this spell that I am not aware of?