I think that having a worldgen option for setting how early (in population) the werebeast attacks can come is a good idea. That would give the opportunity to make everyone happy.
In general in relation to that, I think that the balance of death to external vs internal forces is a little too skewed toward internal now: a lot of the stuff that can attack you has been nerfed and/or doesn't always appear. for example, I see new players often asking things like "am I ever going to get goblins attacking?" And I think the undead need a bit of a buff again. Additionally, I would make it harder to wall yourself off and prevent enemies from coming in. A dirt wall construction shouldn't be completely indestructible in my opinion, for example. It would be a bit much for things to be able to dig in at you, but I think there should be some circumstances where constructions can be unmade by attackers.
However, I think the whole stress thing is a little out of wack. Specifically, the fact that dwarves get stress from seeing the corpses of sentients, regardless of whether they are enemy or ally, is rather extreme in practice. I think it is right and proper for there to be significant negative thoughts from seeing the corpses of their fellow fortressmates, but the effect should be a LOT less for those who have to clean up a bunch of dead troglodytes, or goblins that tried to raid the fort.
Ultimately, It's Fun to lose because you got killed by an enemy attack, and it's also Fun to mess up when playing with water pressure and flood yourself or wreck youself with some self-made disaster like that. Unfortunately, it's not really so fun to have the thing that does you in be things like stress from having to bury the goblins, or a loyalty cascade that is completely inexplicable, even in hindsight. Or additionally, the inevitability of FPS death.
Also, It's difficult to get dwarves to train properly, especially marksdwarves; since it's really hard to get them to shoot at archery targets. It's really difficult to get dwarves to wear the right equipment, and often they get stuck in loops of picking up equipment before going on raids. Also, it's kind of annoying that dwarves can't use the same items/uniforms for both civilian and military use (like the same axe to fall trees and fight, and the same crossbows for hunting and combat) and there's also the raid equipment corruption bug.
Obligatory other things:
yeah, there are a lot of really awkward things about the UI that need to be addressed. I know that's not supposed to be the point here, and that's why it's going in the post script, but here is the one thing about the UI that is by far the most frustrating:
Lists are unsorted and unsortable. Trying to find a unit to assign to a squad can be really troublesome: look at the main unit list, then try to find him in the assign squad list, which is ordered completely differently and doesn't color code the names like the main list. It would be nice to be able to manually sort lists, or use some sorting methods (e.g. alphabatic, or by material, or by skill, etc.).