Merge the "Wood Furnace", "Ashery", "Kiln" to the "Kiln". From research on the subject and personal experience with making charcoal, lye, and potash... There's very little reason to have three buildings for these closely related processes. Most people now and historically, usually, did all their wood burning tasks close to the same firepit, furnace, or kiln.
A "building" in DF is not quite the same as a building in real life. A DF building is a station where an activity takes place. In this case, a wood burner is really just a place where we burn wood to charcoal or ash, with considerations for making the process safer for our dumb dwarves (who can't seem to grasp when they are on fire). An ashery is a place where we turn ash into lye or potash, together with all the paraphenalia we need to do that. The kiln is the only building of this set that is a proper building.
Remove "Pearlash" and replace with using "Potash". Pearlash is just more refined Potash. For the purposes of the game, Potash will work just fine, as Potash was used in glass for quite some time.
I beg to differ. Potash refers to any potassium salt, and can refer to potassium oxide (a fertilizer), potassium hydroxide (caustic potash or lye), potassium chlorate (various uses, including in agriculture), potassium chloride (another fertilizer), potassium nitrate (saltpeter, oxidizing agent, food preservative and yet another fertilizer), and potassium permanganate (various chemical uses) as well as potassium carbonate (pearlash proper). Of these, potassium oxide, potassium chloride, and potassium nitrate are good fertilizers, as potassium is a large percentage of the chemicals by weight. Potassium carbonate (pearlash), however, is much less due to the fact that the carbonate ion is heavier than the other cations (except the nitrate ion) and the fact that it doesn't dissolve readily in water, so it is not nearly as effective at potassium fertilization as the other three.
On the other hand, none of the potashes forms of a major component in glass making except pearlash. You need to be able to refine potash to turn it into an appropriate material for glassmaking. Fertilizer quality potash is not the same as glass quality potash, having quite different chemistry.
Merge "Tanner's Shop" and "Leather Works" to "Leather Works". I could see a little benefit in having a separate building for tanning, but you could just build a dedicated Leather Works off to the side with a work list kept empty to handle automated tanning jobs.
No. As pointed out, tannery is a potential source of unhappy thoughts for dwarves. It's messy and never performed anywhere near where you do leatherworking. By your own standards, they don't belong in the same building. They belong on opposite sides of the fort.
Merge "Kitchen" and "Soap Maker's Workshop" to "Kitchen". Much like the Tanner's Shop, it can be nice to have some distinct separation of buildings for tasks... but soap making isn't too complicated of a process that a Kitchen couldn't handle.
No. Soapmaking involves nasty chemicals (lye), and you don't want it anywhere
near where you prepare food. By your own standards, they don't belong in the same building.
"Lye" should be a more of "Kitchen" task. Lye is made by drenching Potash and collecting what seeps out from the pile. Also... as of right now, Lye could be removed as it's only is used to make soap. Since Lye is made from Potash in a process that could easily done in the process of soap making, Potash could replace the Lye requirements for soap. If Lye starts to be needed elsewhere, it can be added to the Kitchen.
Not only no, but HELL NO! Even dwarves are not stupid enough to prepare a toxic, caustic chemical in the same place they prepare stuff they actually eat.
Merge "Bowyer's Workshop" with "Craftdwarf's Workshop". Woodcrafters in the Craftdwarf's workshop could take care of everything the Bowyer's do, easily.
As others have pointed out, a bowyer is not the same as a woodcrafter. The tools to make a bow or a crossbow are different from the tools of a woodcrafter, and the skill is different, too. Furthermore, although dwarves only use crossbows, DF is not a dwarf-only game: each civ in the game is potentially playable with the addition of a single tag, and other civs can find more use out of the bowyer, such as making blowpipes, self bows, and compound bows.
Merge "Dyer's Shop" and "Loom" to "Textile Workshop". The Loom and Dyer's Shop are closely related and could be merged without changing the game much. As with the Tanner's shop merge, you can set aside a Textile Workshop to handle automated tasks that the Loom does. This also reduces the amount of stuff needing to be hauled around between different shops.
No. Dyeing, like soapmaking, is a messy process. You don't want to dye anywhere near your loom, where aerosolized dyes can migrate to the work currently on the loom and stain it.
I love Dwarf Fortress, but it has some SERIOUS numeric, fodder, item, skill and process glut.
Most of the glut is taken up by pathfinding. Your improvements will not be significant. Further, you are eliminating only a few of the many tasks/items that the game offers.
Complicated is good, but you have to be complicated with decent enough reasons or it just gets annoying. From the experiences of designing my own pen and paper RPG with tweaking mechanics, defining skill lists, and reducing the system to key components and getting rid of extraneous parts... You need to know when to prune. It seems like DF was pretty front heavy early on and it might be time to cut back a few things to allow the rest of the game room to grow correctly. And anyway, anything removed can ALWAYS be added later when it is needed again.
The Dwarf Fortress part of DF is not an RPG — it's a realtime strategy game. RPGs and RTSes are quite different beasts, with different dynamics and draws. In RTSes, resource and task management is part of the fun, and the Fun.
We know that several of your suggestions for pruning, such as animal dissection (which is not nearly the same skill as butchery), are slated for improvements by Toady that will hopefully pay for their inclusion with enriched gameplay. Until their full form and utility emerges, we cannot evaluate whether or not they need to be axed, and until then, they are completely ignorable.
What DF needs is not reduction, but streamlining. The manager has a more substantial task to do than merely okaying a bunch of busywork. A proper manager will be able to manage entire production chains, making sure things get done in the right order, and that sufficient resources are availible and reserved for the tasks.