Of course, ranks are only meaningful within the organization that issues them - but your organization is the Aikikai, and it's sort of odd, IMO, that certificates that are issued by the same organization and signed by the same person (since all Aikikai yudansha certificates come from hombu and are signed by Moriteru Ueshiba) have such a varying range.
My opinion? The time requirements in the US have become much too long. 8-10 years for shodan? In some of the old schools you could get a menkyo kaiden in that same length of time. It creates an over-emphasis on the value of the "black belt".
Actually, I don't find it odd in the least. The Aikikai Hombu doesn't set the standards for the USAF; the Technical Committe of the USAF does. Sure, it's Doshu signing the certificate at shodan and up, but it's the Shihan of the USAF who tests us. If Hombu dictated that our tests should be the same as theirs but then the time requirements were different, then I would find that odd. But, that is not the case, now is it? The USAF Technical Committe are looking for us to demonstrate a competent understanding and clear fluent skill of all the basics at shodan. Shodan isn't THE beginning of our Aikido training it is just ANOTHER beginning.
Emphasis on shodan, sure, why not? It's better than emphasizing it by de-emphasizing it. I find things more honest by acknowledging that it actually means something more than the $15 dollars that you could spend at the local martial arts supply store.
I agree shodan is not the end all be all to training. But, I find nothing wrong with giving a person a long-term goal which expects you to persevere and find a greater purpose to their aikido journey.