I agree with it. From the beginning of the story we're conditioned to fight against transforming.
So no, at the end I can't possibly decide to become illithid myself. So I must choose between either the emperor or Orpheus. It would be great if the emperor could stay in its form and Orpheus joins as well.
But there's a related issue
Not willing to become mindflayer myself I 've been grooming Gale to take that role from Act 1. I gave him the astral tadpole and as many tadpoles as he could swallow. But in the end, neither the emperor nor Orpheus want to consider his offer. They only want to negociate with "the leader", being the PC. That's a disappointment after many hours of planning and weeks of play to see the plan blocked this way right at the end.