Well, if it’s worth mentioning twice …
☼Cathedral☼ was started as a religious-themed fort so perhaps it will serve as an example of ‘how it can be done.’ The defensive dust cloud thrown around by the earth mage is certainly useful, as it hides him and everyone close by from incoming projectiles. The rules seem to change quite a bit with each new release and that may be preventing most everyone else from having the data of “ten, ten-year forts” for evaluation.
Just from my limited experience, praying is too “iffy” – possible exception of mood items – and the Bloody Armor is too heavy to be of practical use. Some of the other mage skills look good in theory but I’ve never been able to skill one up sufficiently between releases. In ☼Bannerheart☼, the Iron Colossus was one kick-ass defender to be sure; even busted up, he could more than hold his own against a squad of armored Orcs (btw, is it possible to heal/fix those things?) but there’s another way to obtain one in the current release besides praying. You tend to nerf things when they get too good.
Even with current limitations, souls are still worth the effort but it used to be pretty easy with changelings to have legendary skills. I stayed with ☼Bannerheart☼ another couple of years after the FPS was fixed because it was such an outstanding fort and it was fun to watch the steel-clad raptors and sauropods make short work of even large invasions. After a flippin’ year of RL time, I’ve managed to learn the tricks to having a decent military from the get-go (with your early help, thanks for that)
Embark with plenty of the cheap leatherwing bats and something to give chiten when butchered and you can have good armor even before the autumn caravan. Turn off auto-tan and use dedicated stockpiles to make studded leather, which is good enough for the first two years if you keep total wealth below the trigger. ASAP, make chiten cloaks: they’re equal to iron but lightweight and multiple cloaks can be stacked without going over the size restrictions, training the dorfs in armor-wearing. Spend embark points on a good weaponsmith and Guild him right away; the trap components are the best early trade goods and he’ll soon be making masterwork weapons. Use light wooden shields until you have enough of the better-coverage bloodsteel shields from trade – wooden shieds will train the skill and they can still cave in the skull of an iron-helmed invader. Improve all squad skills by hunting to prep them for the heavy metal armor. Use some of the early steel to make battlepicks which are very effective in the hands of a skilled miner (trade away all others). Quality helms and mailshirts are an early priority, hopefully with breastplates before elite marksinvaders come; everything else is just down time in the infirmary unless the fortress has the resources for full armor sets. Trade for all the silver and titanium you can, the Alchemist is just too damn slow and Teduk is too expensive and never has enough, anyhow. Mithril edges are more than good enough even after the trigger until you get Volcanic. Then, on to clown-town!
but there’s always something new and interesting in each subsequent release. The library, for instance, was the best way to train dwarves to great agility (the most useful military skill; armor is good, not getting hit is better) and sufficient armor-wearing to handle the heavy metals. And skilled soldiers encased in steel are good enough until way late in the game. The library is still ‘good enough’ with level 5, but I preferred the “slow but sure” rules previously to higher levels. But then, I like the long game with quasi-historical accuracy and mega-projects while most players are likely “slash and kill” fans.
When someone demonstrates an effective way to employ all the new magic from scratch, that’ll be one less humongous learning curve and a great help.