As someone who's played all roles in this story (candidate, interviewer, hiring manager, person designing the process) I'm going to argue that symmetry is more

As someone who's played all roles in this story (candidate, interviewer, hiring manager, person designing the process) I'm going to argue that symmetry is more important than length. By symmetry, I mean that at any point in the process, you and the company have invested the same amount and learned the same amount. If you're going to give me 5 interviews where I'm answering 90% or 100% of the questions, go away. If you're going to give me 5 interviews, where the first one is the hiring manager mostly telling me about the company and the role, the middle two or three are about 75% me answering, and the last one or two are mostly me getting to know some people I'm going to work with, that does seem long, but at least it's balanced. This is a big decision for the candidate as well, so presumably if the process is fair both the candidate and the company should want a process of the same length