Re: The purpose of Aikido?
I would say each individual's "objective measures of how good one is at aikido," is different for each individual also. For some it maybe having a sense of accomplishment is good enough; not seeking perfection, but acquaint to fairly decent. Others the application of or commitment to the spiritual dimensions found in Aikido. For some it is being a good teacher, or being able to thwart a mugger. Or decelerate a conflict or potential hostile situation be it verbal or physical. It is all up to the individual's personal criteria, something not judged.
People fail to see the dynamic sphere that Aikido is. It is not a single minded, single dimension activity. It wasn't made for combat, but rather for the soul.