I've played a couple 5 year forts now, trying different things such as:
* Timbermill and tree-farm equipped embark in a badlands. worked great, still have to import wood but the mill gets you through through between caravans. I still agree requirement of blocks for rock bins is a good idea, it's not *too* hard to get them but gives some incentive to have wood). Experienced FUN initiated by Burning skulls and resulting tantrum spiral (even though they're no longer impossible to kill, they're still quite dangerous if you don't design your fort specifically to be fire safe. much more dangerous than the other Skull types). A Shadowmancer migrant seemed to turn the tides, he killed off a goblin siege almost single handedly, but then he helped set up the WORST dwarven hospital i've ever seen. Not only did no patients survive, but he'd raise them from the dead, kill them again, and throw them in a unmarked mass grave. Later he got a vampire nurse as an assistant. Together they must have killed about 25 patients. They eventually went down to a seige with multiple elite bowgoblins, so overall i'll call this fort a success.
* Miner embark, straight for the 2nd cavern, using nether-wood leather and crystal pikes. It's an interesting risk/reward, the equipment is pretty decent and once you've carved out a safe spot you just have to harvest it easily, but the caverns aren't totally safe. Experienced FUN by delving too deep trying to test the new temples.
* Craftsman embark, trade mastercraft goods ASAP for Slade turrets, drakes, the new Trade goods of steel bars / armor / etc. Works like a charm. No need for deep mining, just need a bit of silver for runes / armor plates. Orc, goblin, frogmen sieging so far but no problem. The turrets nicely fire at different Z levels and through fortifications with no pathing problems. Trap components upgraded at the engineer's shop are powerful but the balance seems OK, with the amount of cloth required and the multi steps to make them. But they're brutal once they're installed. Again, the closest we came to trouble was burning skulls.
There might be a bug, that it seems able to always train Siege operation at the War Library even without books, and I saw a guy there reading a Toy Merfolk Farm. Didn't yet try to track this one down in the details.
Furniture workshop and other Batch operations, although I don't use them too much early on it seems a nice option once the fort starts to get big (I used some of the fix discussed in the main thread to avoid the 150x bug).
Bladed crossbows get material from the bayonet was pretty key fix, very nice.
It seems really hard to notice any skill increase happen from using the libraries, especially considering the amount of resources and complexity the books consume. It would be OK except that none of the objects are convenient to stockpile so it's very hard to set up a recurring "library industry".
Leather stockpiles don't seem to obey when I say to not stockpile lamellar in the main pile.
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Oh, caverns. I really like the 1st and 2nd cavern overhaul, but I find that I really don't want to open up the 3rd cavern any more. Two reasons, one is simply aesthetic, the writhing worms getting into all the soil layers. The second is a real reason. once the fire trees start growing everywhere, it's quite dangerous to harvest trees even in the soil layers of your fort. So there's a really strong disincentive to even explore deep parts of the map, almost enough to be not worth looking for magma because it's such a pain if you happen to breach that cavern. I was inclined to dislike the facehugger vermin, but to be honest i saw them, but didn't notice any effects.