Hi Keath and Fritz,
Based on a (maybe incorrect) assumption that there are more people capable of taking the role it sounds like you have a genuine tension about this. One important thing is that more people are willing to take on the role in order for you to be able to move forward. Also ask yourself the question is there harm in always having the same person as the Facilitator, especially if the person is doing a good job... Then again, having been facilitator for a while in our company, the experience deepens the insights and knowledge on Holacracy, sometime even the hard way that leads you to say "I need to look into this because I don't know, give me a few moments..."
to go back to your tension, you can process this through governance, what about a policy that says that if a person is re-elected for x times, he cannot be re-elected for the next term (but can again for the term thereafter..). The basis of the tension must be a correct one of course, you see an opportunity for the organisation to move forward..
Another idea is to start in the Tactical meeting, asking for information on why people seem to want to stay with the good old and not try something new (i.e. Facilitator that has not a lot of experience yet).
From personal experience I must say that following a training helps to get you in the right mode of being a Facilitator. There are quite a few little knacks that help you be a good one and not muddling along. (just one example, get in your curiosity mode when testing objections - makes a world of difference and keeps the objector out of defense mode...)
just as curiocity How does your election process go... I have been handed a quite good process to get the election moving perfectly. I'm not sure if it's developed or used by Holacracy one, but it works for us anyway...
looking forward on your thoughts on this subject..