a) It's interesting to take a peek at the Micro Lutheran Denominations in Pastor Zip's enumeration. Lots of them are split off of the right edge, either in terms of things like women's voting privileges or kind of the liturgical/eccleisal right - ELDoNA comes to mind. Many of them seem to me to be one generation denominations - when this generation of pastors retires, who's going to replace them?
b) Which leads to Apostolic Succession. Here's the Wikipedia article on the topic, with much to check out when it comes to Lutherans - https://en.wikipedia.org/wiki/Apostolic_succession. Since the Apostles' Teaching is what's historically been at the heart of it for Lutherans, it's kind of difficult to get wound up over the other point of view, which is biological and ontological. And yet many do. Certainly it's a distinctive for the RCC.
It's one of those inside out things where Lutherans tend to think of it as adiaphora and extra-biblical and those with it, who are accused to adding to the biblical record with (oh, no) the traditions of the church catholic through history point to the Biblical record. "You are Peter and upon this Rock" is right there in the Bible but we Lutherans interpret the Rock to be Apostolic Teaching based on his confession, even though the resultant gift of binding and loosing is given to Peter in the second person singular - that is to him personally - and not to all the disciples in that passage. Am I wrong there? That's the way it reads to me. So we take our reading off of "They continued steadfast in the apostles' teaching and fellowship" in Acts.
Ecclesiology. A soft spot, a weak spot, a chink in the Lutheran armor.
Dave Benke
That is what is always interesting in teaching confirmation classes on the part of the catechism that in my experience is often skipped - Absolution and the Office of the Keys.
Yes, it is often way beyond half the kids, but not the half that needs to hear it; I jump into a big word - hermeneutics - or just method of interpretation. And that section becomes something of a capstone. "What you have been doing the past year and a half has been learning a way of living with biblical authority - you interpret it with help from the church and it interprets you as it binds and looses." It is also a beginning of sorts in that I've literally had the question posed to me "well, what system is our real school teaching us?" To which I answered, "great question, maybe you should find out." (The real answer as far as I can tell is nothing, modern education is nihilist, the only thing that matters and only for a time is power.) And the big place is listing out Matt 16:18-19, Matt 18:18 and John 20:23 and asking, what do you do with this? Forgiveness and binding seems important. Who has the authority? Or is this enough of a discrepancy to just pitch the entire thing? And you walk through what various groups teach. You bring in the Smalcald Article III.4 on the Gospel.
It seems like a week spot, ecclesiology, and maybe it is. But in that conversation, the Lutheran church is the only one that attempts to keep all those truths instead of pitching the rest in favor of the favorite one.