I know I'm repeating myself but I like all this discussion, so I want to add my two cents. Do we really need to be Thungni's heir to be Thungi's heir?
Let me elaborate. After taking heir title even in the best case an insignificant part of runesmiths won't be fine with us. I want to focus on this "minority". What will happen to them or to be more specific what will happen to Vragni? I like "Dinkleberg!" memes and T-posing on the guy but he is despite everything a well-respected runelord in his hold and region. One may even say his quality work and productivity rate rival Snorri himself. He is a bit of wazzok sometimes but is still a net positive for those around him. Yes, he does grumble and even slander Snorri but he also has done much for dwarves around him.
Where I'm going with this is, what will happen to everyone who disagrees with Snorri if we are accepted as heir. (Whether the rest of the runesmiths will accept him or not has already been argued by many, so I won't talk about it and assume the best.) Snorri, tho he has already achieved much is not the only who has the only right ideas about everything. There are other runelords, conservative or otherwise, who can push and have already pushed runesmithing forward. Snorri's way is not the only way forward.
What if Snorri was an accepted heir when we built Khazagar? What would others do? They would grumble a bit, say "As expected of Thungni's heir" and at best case, they would simply copy the Khazagar. There wouldn't be any Citadel of Creation in Ornsmotek or other things that the southern holds are cooking.
Snorri will keep getting older, his accomplishments will grow, and he will probably crack Consternation, and with hammer and title who will really oppose him then? Those who simply don't agree with Snorri get crushed under everything. Sooner or later there wont be other schools of thought other than "Snorrism".
As an argument, I see some say we can be a silent neutral arbiter like Thungni but I don't think it will work. In Thungni's silence people could come up with their ideas and had room to argue, ancestor only had to intervene when things got really heated like that one in Conclave. Snorri's silence won't be the same one as Thungi's. Snorri is pretty much a hermit in far North but due to his actions and deeds people still try to "copy" him. Many runesmiths in Kraka Drak call themself not slightly less conservative, not even radical but straight up "Snorrist" and yet Snorri pretty much didn't say anything in his own hold too.
I understand why people want to take the title. It will help us stop rune-lore from being lost in up-coming tragedies and disasters, it will help use shape the guild into a better one than in the canon but do we really need to be Thungni's heir to do all these? With having hammer we will have quite a bit of prestige, why should longer path be impossible?
If we want to take a more central role in the future of guild, we can do it without constraining ourselves and the other runesmiths. We can start to talk and write more to other runelords. Open more dialogues, build ties, discuss and grumble at each other. We can try to be less of a hermit while still being usual weird rune-santa.
There is also this line, alongside soulcake saying all this is Snorri's interpretation which was in part the inspiration for most of this rant. I don't know if he is really in a good headspace to take this role:
At the end, I believe we can still do much and even worthy of being Durin's heir without taking any title. It will be hard but anything worth doing is.
English isn't my first language so I'm really sory for any mistakes and for the long rant. As a last note thanks to soulcake for the quest, can't wait to read more.