Vanilla DF2012 is unplayable on its own. For eg.: the military is untrainable in the official release. They take forever to equip themselves, and even if you manage to get them to train they soon go unhappy. (and quite possibly on a berserker rage...) You either need to use the danger room exploit, or DFhack -snip-
It's almost a year since the latest release, these bugs are well known and documented, but still part of the code. And don't get me started on the UI...
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Final words and my 2cents: If Toady wants 100% control over the codebase, that's his choice, but then he needs to work on a tighter release cycle and iron out at least the gamebreaker bugs. The other solution is that the DFhack plugins/fixes need to be officially distributed as a part of the game. (Which are ok on windows, but need wine on linux or mac, bringing their own problems along...)
Now, I haven't been around nearly as long as some of the other members here, but as someone who exclusively plays vanilla I can say that vanilla military dwarves do NOT take forever to equip, do NOT take forever to train, and you do NOT need a danger room. I just bring a teacher/armor/weapon user at embark, make his gear first, then activate him. He grabs his gear, trains, spars with a buddy, and they both hit legendary in weapon skills in a year or so. My current fort has nothing but legendary dwarves in the militia, all they do is spar. Sure its confusing to get them to actually spar, but all you do is set their schedule to train with 2 dwarves.
The bugs aren't really noticeable to me, but I've been working around them when I can, and avoiding them if possible. I don't have a problem with hospitals (no containers in the hospital, just stockpiles) and I haven't noticed any more serious ones yet, unless you count the appraiser migrants being flagged as traders and blocking migrants coming in, but thats not even horrible and game-breaking.
And as to the release schedule, its one guy and his brother, and only one of them really codes anything and implements it into the game. DFHack is useful, and does contain fixes, but its really not essential to the playability of the game in my opinion. I'm content to play with what I have, and wait on yearly releases and wonder what kind of possibilities exist within the new updates rather than demand fresh new content that is crap every month or so. That is one reason why I've almost totally stopped playing other games, crappy new content meant to siphon my money out of my pocket (I'm looking at you, EA, Activision, etc etc)