Questions from a devil's advocate point of view:
1. What does rank represent, and why is it needed?
2. If some consideration other than technical skill is needed for rank, how then does one reconcile high ranking aikidoka (including shihan) who clearly do not have a strong moral character? (ie Sex, Lies & Aikido Senseis by David Lynch)
I don't expect answers to either of these questions, I ask them for retorical purposes only.