I guess the questions for me and my psychiatrist would be:

"Am I getting better given the treatment of the current diagnosis?"

"How would my life be better if I got a different diagnosis?"

"Would by course of my treatment be different with a different diagnosis?"

I don't know if I would blindly trust my psychiatrist, especially if I thought I could be better than I am now, but if little would change, I would think my diagnosis as just words on a page.