Atm I think, if you picked an embark where you won't get sieged, you picked a crappy embark/genned a crappy world if you wanted to be sieged. I've never played pre-42.06, but deciding your neighbours, their locations and
their neighbours + sometimes their relations is part of embark prep.
However, the problem remains, if you embarked on an island.
With pre-set values, it's not that difficult to gen a world where your embark is the only thing goblins can target and only from a dark fortress - or to even ensure they had your fortress in range in worldgen to ensure a war/dead civ.
Though, for larger worlds the civ locations get stretched out, I think, so it becomes bit more difficult - another reason to not brother with them.
Admittedly, by my convo with IlFedaykin, fortress defence races tend to be able to build civ anywhere calm, so that's an additional complication if you want each and every race of the 18 others to be able to meet you on embark without being able to attack anyone else in worldgen.
Alternatively, if you don't mind cheating there's
dfhack script to move sites in fort mode, though you probably still have to ensure you're the only valid target with setting up land like star in the ocean.
As for the humans remaining same, it's more than just a caste system - no taverns, libraries and temples cuts down the human growth potential in worldgen and things in fort mode as well (what's with the centerpiece tavern), no world activation alongside that probably stunts the pool of visitors you get, you'll have to deal with the old emotion system that made 5-year olds seem mature, it was before the jobs rewrite so there's those hauling problems and likely stockpile links needed for materials, it was before new plants so aboveground you'll have trees give 1 log and only like two dozen things to harvest, people would pass out right away from broken bones and be unable to multi-attack as far as combat goes....
Probably tons more. There's large differences between 43.05 and 34.11
PS: Yeah, I know you can write a story without any or almost any untimely death in populace, like in the early days of Breadbowl where baby drowning in a well was the worst thing in years, but not something you want to do