I can understand both your points of view, but lean more towards Crimion.
For example, in BG 2, if you attack Aran Linvail, an assassin appears and kills you immediately, simply because Aran is a necessary NPC for the story. On the other hand, you could solve it the way they did with other NPCs, which is that they teleport away as soon as they are attacked.
In the specific case of Gale, I would prefer that, unless he is part of the party. Then you still have the opportunity to meet him later when you find out more about him.
After all, it is rumored that some of the companions, probably pretty much the ones who are not actively in your party, will die at the end of Act 1 anyway, which means that we will be confronted with the problem of Gale as a living bomb again.... So there should be a solution to his so-called "uniqueness".
