I was schooled on roguelikes (NetHack, TOME, Dungeon Crawl) so I was already used to games that reward patience and a strange ability to memorize ASCII characters (or whatever the tileset is called.) And I'm used to games that are capricious if not malicious by design.
I think, having played this off and on for a year or so, that if your goal is to have a reasonable game with reasonable challenges, it's not incredibly hard. Someone else mentioned the wiki tutorial, and I find that if you follow that to the letter it's almost too easy, and the rest you pick up by trial and error.
Now, like the OP, I'm playing pretty exclusively in "Reasonable" biomes. No undead. No freezing or scalding. Iron ore on site. By DF standards, you could say I'm spoiled. And you're probably right. Here's a thought:
For these luxurious locations, there needs to be something...more. Something Dwarfy. Something worth looking at. I now regret somewhat having used the tutorial because when I start I have to work twice as hard to avoid recreating the same staircase-centered, vaguely cross-shaped layout that's the most reasonable. I want to do something that is still functional, but perhaps more interesting or beautiful to behold.
I think I'm going to play my current fortress (worksack, where you can't swing your pick without hitting a magnetite cluster laced with bituminous coal) until it becomes a monarchy (which I think it will if I remember to bribe the dwarven liaison sufficiently) then let it go to hell, so to speak, because it's what I always did on Sim City when I got bored with a game. Or maybe I'll just save it and start something new.
But it's hard now because once you build a very standardized, efficient, survival-oriented fortress that can comfortably house over 200 dwarves with (usually) fewer than 10 casualties per year, it's a hard pattern to break.
That, or I should embark next to a necromancer's tower, but zombies are icky. Hmm...