Good article and agree with a lot of what you said. Major exception is,
In Aikido, the ability to apply the principles practically is the measure of your progress. The greater the ability , the greater the progress.
What other way is there to measure your progress?
The dojo is a laboratory... in a lab one controls the conditions. There are people who can do absolutely amazing things in the lab. Their mastery of the principles is very high but their ability to apply those principles outside the lab is not necessarily the same. The reason is that the outer forms must change based on what the application is. If one has not trained specifically in the forms for application of the principles in a fighting context, then one is not going to be able to successfully apply the principles.
The outer form of Aikido is not particularly geared for fighting. It does a lot of things but fighting isn't one of them.