Actually, I planned on writing a blog post on this at some point. I work at Hired, and we had an interview process to determine who (internally) would become the next manager. This involved three interviews with engineers, and a presentation with management.

That sounds humiliating for candidates who don't make it. Especially having to go back to work with the engineers that rejected them.

In the "traditional" method of selecting a manager, most engineers don't get selected either. However, the process is less transparent that way.

I'm saying this as a candidate that didn't get selected. I got great actionable feedback on how to be a better leader, and I'll keep my fingers crossed when there is another opportunity available.