While I understand the sentiment, I think that "trust in our friendship/love" is the better reason not to explode for companion Gale here. He is terrified and thinks that he has to do as Mystra commands because you mere mortals can't possibly take down such an enemy. Reason does not really combat that, it's a question of trust. Trust me that we can do this. (I dislike the "This is not your decision to make" option much more.)
I certainly don't want to take away existing dialogue options, but I would like expanded options. My more logical characters would try appealing to logic. I would love if the "trust that we can do this" option included a way to talk about how that Elminster's "be a moon Unto yourself" speech was encouraging him to find another way. Elminster thinking there's a better way seems like a big deal, both logically and emotionally.
But I think there should be some sort of check or quest progression for Avatar-Gale, because in Gale's Origin both Tara and Elminster tell you to use your head to figure out what's going on, so it would be neat if the quest-log reflected that. Ideally it would be cute if your companion staged an intervention and gave you a pep talk before entering the final room, or you could talk things through with Tara at some point, but I understand that's way more effort than updating the chat log at least.
I like these ideas. The companions have supportive dialogue when Gale first gets his orders... at least if you're not playing as Gale. I could only get Wyll or Lae'zel to react when I was playing as Gale. It would be nice if they all said something, and if they brought it up again.
