DF could use much better procedural generation, I think. It doesn't have enough variety to actually feel different enough game to game. Changes that would fix this (while also explaining what I mean more):
1) Caverns just KILL diversity. Every. single. map. I am guaranteed huge forests and almost always water and a full set of reliable crops and stones and huntable creatures. No matter where I begin. Which is just very counter productive as it undermines almost the entire map gen process. Caverns are fun and all, but should be randomly scattered around only. Maybe something like 20% of 4x4 embarks have any at all, in total, and 60% of 4x4 sections of mountain connect to caverns.
2) The high redundancy of crops makes it uninteresting which crops you get. Every biome that grows anything grows fiber, booze, and food crops in triplicate or whatever. And due to #1, you also have all types again subterranean. I admit food and booze must go hand in hand (you can ferment almost anything), but fiber and many other products in the future (like alchemy stuff or medicines) could be very biome-dependent, leading to different stresses in different games.
3) Not sure what to do about it, but: almost every embark has a an awfully large variety of metals and magma safe stones, to the point where worrying much about these is fairly optional.
4) The temperature underground is always 47 degrees fahrenheit everywhere in the world all the time ever. Which minimizes the amount I care about diverse surface temperatures (which themselves already aren't actually that diverse because there is no increased dehydration, hardly ever any frostbite in any reasonable timeframe). It would add realism and more importantly gameplay diversity, if temperature was more acutely felt requiring crop differences and clothing differences, and if the underground temperature correctly mirrored the climate (20-30 feet below, it is a constant temperature seasonally, BUT this constant temp will be much much lower near the arctic than near the equator). Also, magma tubes only slightly warming rock 3 feet away is more than a little silly and contributes to maps all feeling uniform, with a volcano for instance having shockingly little influence on gameplay other than the convenience of not building a stack.
5) Other aspects of map diversity similarly don't matter much, but I'm rambling on too long already. Elevation affects basically nothing other than making it annoying to follow creatures around. Rainfall has no effect on crops or anything, thus is irrelevant outside of evil biomes. Rivers and oceans are bizarrely usually LESS useful than ubiquitous aquifers. Etc.
It's certainly not BAD. But there's a ton of room for improvement. And this is one of the better games for procedural gen.