I used to get the yucks of teaching about every seven years. I noticed the pattern after the third round.
Martial Arts is a strange endeavor. We lead and hope that they will follow. The problem is that every practitioner travels his own path. We can't ask for them to be us any more than they can hope to be us. The hard part is letting go and watching them create tiny branches of the tree you started.
I used to take my students to my instructor for black belt testing. The first thing they heard from him was that they would not be there if they were not ready. Then he proceeded to put them through the most grueling ordeal they have ever had.
Each of my black belts were so different from each other and, of course, me but they all deserved their belts.
I agree that it might be useful to step back and let someone else evaluate them. An occasional field trip could be useful from time to time. I suspect that you will be pleasantly surprised.