Having read through the article a couple of times I believe the only issues I can see that I can comment on (and there aren't many) are the oral traditions, the Lodges and the Whisperkin.
Now, oral tradition is a good way to differentiate your chapter. But what happens when the chapter suffers heavy or catastrophic losses? Many tales would be lost forever more. Come to think of it - I suspect the chapter has likely lost many tales and sagas over the millennia as those who know them have died. It's a bit like the Spartans; they only ever had an oral tradition and so all we know of them these days, since the realm and people have passed into history, is recorded details made by their rivals, neighbours and enemies. Perhaps this is how some of the older details of the chapter is preserved - by other people and chapters making their own records.
I don't see anything wrong with losing stories. Well, the Arrows would be upset about it, but that's the way things go when you don't write things down. It could be interesting to have a few excerpts from other organizations' or forces' records in the IA, but I don't imagine the Arrows themselves would pay those reports much mind.
The Lodges sound like they are meant to be clubs for those who have permanently strayed from the path of being a tactical marine, and while this is fine in itself, there is the undertone of the Lodges from the Horus Heresy books. The thing is, by logic, these Lodges would be relatively small brotherhoods, considering that not all members represent their chosen obsession throughout the chapter. There are regular brothers simply moving on their way through onto becoming a tactical marine. In my head, these fraternal bodies would number, each, at less than fifty. Which means that, if these are old fraternities, then their purpose now might have been different to what they were centuries or millennia ago. Surely, at some point or another, these fraternities have needed to be refounded, rebuilt and revived - but with new men and possibly differing attitudes to the previous incumbents.
Firstly, the Lodges may very well be small. They are effectively the veteran companies of heavy support and assault, and while that does sound a bit eldar-y, you could also just look at them as the equivalent of Vanguard or Sternguard or Terminator troops: Marines that have specialized in one field at the exclusion of all others. The difference is that the Arrows put such emphasis on the Bolter that these sorts of troops are relatively rare. The Long Bows would likely have a decent stock of brothers, because there isn't a huge gap in practice between shooting a Bolter and shooting a Heavy Bolter. Talons, on the other hand, would likely always be a small fraternity (likely in the 50 or less number you mentioned), seeing as its such a deviation from the main teachings of the Chapter and Lacrum. But as Veterans and particularly useful groups, they'd carry a weight beyond their simple numbers in the politics of the Chapter.
On the second point, they almost definitely aren't what they originally were, or at least they didn't exist when the Chapter was founded. It's a result of the slow creep of Lacrum's culture into the Chapter's identity, no different from the reverence for the Bolter or fire-base tactics. As for whether or not they change, fade, rebuild and re-identify themselves as time passes, it's quite possible. The question is, how specific do I get on these points in the IA? Obviously I don't want to list out every Lodge to ever come and go. It may be suitable to simply mention that these things have a way of changing over time, but for some time now it has had the structure of the Long Bows and Talons.
On another point, after the (very) short story above, I think I'll have to write up a story or two for the fluff section. Not that I haven't tried already mind you, but inspiration flows in sputters, with long periods of garbage in between.
And the Whisperkin - something feels off about the Whisperkin, to me. I think, perhaps, they don't need to be there. It treads on special snowflake territory, imho, and feels like it's been influenced by the Horus Heresy Raven Guard Shadowmasters. If the intent wasn't for this to be this way, then I advise writing the Whisperkin differently. Perhaps make them penitents? I don't know. I just think they don't need to exist in their present form, if at all.
They're meant to skirt the edges of snowflake territory, just like Lone Wolves, Death Company, Wulfen, Mantis Warrior Matrix guys, etc. They're unique and above the norm, but they aren't gods, and they come with the drawback of genetic infertility. And quite likely a much shorter expected life-span, given their connected urge to forge a legend for themselves.
I've never heard of the Shadowmasters, but it's a cool name
However, I've thought about them a lot. One of my favorite ideas is something along the lines of a peculiar synesteshia. Wind patterns, barometric pressure, sound and such turning to things like swirling colors and such. Literally being able to see the air, in a sense. It's just a spitballed idea, and maybe one I'll save for a character in a story or something, rather than making it universal.
But on that point, I do think it may
be a good idea to standardize the effects of the Ghost, rather than have it be 'they're all better at one thing or another.' A more formalized set of symptoms definitely, and perhaps Whisperkin simply use those effects to different ends.
Rewrites aside, I'm definitely keeping them in one form or another
Onto good things. I like the altercation with the Throneguard, but I think this bit needs a little more fleshing out as it feels a little bit vague (I know it's supposed to be vague but I want more) - maybe you could include a sidebar from their perspective?
Maybe. I have a hard time with sidebars. It's difficult to make something sound good, yet succinct enough to fit in a reasonable space. It's worth mulling over though.
The first sidebar is good - telling the audience about how the Broken Arrows treat their weaponry adds character. I'm not much of a fan of the second sidebar, though. It's got a decent premise but it feels clunky. I think editing it down somehow might help.
I've rewritten that damn sidebar a hundred times, and I'm still never happy with it
I love the character, but like I said, sidebars are hard.
So there we go, that's my take atm. Apologies to you Firepower, for taking so unforgivably long to provide feedback.
Yes, yes. Paddlins and such.