This mod inspired me to actually get around to creating an account on these forums (which is saying a lot, since I normally stay off forums).
Honestly, this is just pure awesome. I know people have said it before, but this really feels like an extension of the original game. I don't even play vanilla DF anymore. It's just not as fun without adamatine giant forks...
I just wanted to point a few things out:
Back in a fort I had in 0.14a, my legendary weaponsmith created an adamantine mace at the weapons lab. Admittedly, demons were overrunning the fort at the time, so he was probably feeling some pressure, but I think you said somewhere that you had disallowed some possible combinations due to being worthless, like an addy war hammer, and an addy mace doesn't seem much better. I know this is from a earlier version, but I didn't see anything in the notes saying this was modified, so I figured I'd mention it.
Second, the nephilim are really odd when sieging (at least compared to other races I've seen). If they come on mounts, they just mill around randomly. Sometimes they set up camps, other times just wander, kinda like some human sieges. Except that when I charge them with my dwarves, they're still just milling around. They attack if my dwarves are in reach, but if they're even a square out of reach, they don't seem to path toward the dwarf; just random wandering until they decide to run. Because of this, only their archers seem any good at all, and those are weaker than they would be on foot, since they can't fly while mounted.
That, and in 3 years of sieging me 3 seasons out of the year, they almost always wore cloth, even the elites (some had bismuth bronze); no steel, even though they used steel arrows. I suppose I might have just had bad luck.
And it's entirely possible to trade with the nephilim regularly. You just have to abuse the AI pathfinding. Use the Depot Access tool to force all caravans to spawn at one location by building a 5-wide road to the edge of the map, and make sure none of the other map edges are marked Depot accessible. Then build walls along the edges of the road, and build a roof over it to created a tunnel to your Depot. The walls won't be able to get to the edge, but the floor/roof can cover everything. Just be careful that building to the edge doesn't create a valid spawn point on the roof instead.
As long as the AI pathfinding says the road is the quickest map, they won't fly, and will unload their goods like normal. Honestly, though, since they come 3 seasons a year, you need a huge amount of trade goods - those steel goods mean that their caravans are often worth more than everyone else, excluding when the dwarven caravan decides to bring those 20k+ decorated iovium trap pieces.
It's over-complicated and probably not worth it for most people, but it was a nice megaproject to build a tunnel all the way across the map. Of course, you could just build the Depot next to the map edge.
Oh, and I just got the same thing in my embark group like Mistercheif. And I was getting excited about finding something nobody else had mentioned, and then I see that ... Oh well. Anyway, I noticed that he had Proficient Blowgunner and Liar as well as the skills I gave him on the embark screen. Do they just get two random additional skills or something?
Anyway, thanks so much for making this mod! I'm looking forward to the next version!