Honestly having an extra set of specialized custom auto-workshops sounds like the most useful thing ever- especially if they're limited to materials in their burrow.
You could extend the automatic wood furnace to a whole automatic clear glass industry, whereby you just have to designate the trees to be cut and the dwarves will do everything they have to to make clear glass goblets by themselves. You could even set up the forests outside as multiple burrows and have each one bring wood to a different burrow, so as to, for instance, have 1/4th turned into ash (and eventually clear glass), 1/4th turned into charcoal (and eventually steel), and 1/2 sent to the carpenter's shop.
You'll never have to worry about setting plants to be brewed again, just make it so there's a brewer that automatically brews any plant in its burrow. And then a kitchen that automatically brews alcohol, but make it so that the bottom half of the booze stockpile is in its burrow, making it so it'll only cook surplus booze. Set what to grow each season and your food will be taken care of by itself. Forever.
Set up a furnace that smelts any and every ore automatically, with an automatic steel process if needed as well, and then set up an automatic forge that turns all undesirable metals into bins.
The best bit is, thanks to burrows, you can assign a specific number of dwarves to haul exclusively between certain automatic workshops and their stockpiles, so everything is kept nice and efficient.
Burrows and custom auto-workshops, both of which seemed to have been added as afterthoughts, make me a hundred times more giddy than all the other improvements this next version will see combined.
You could always cheat and have the custom shops make ridiculous stuff, which would ruin things, but it would it would be so much more fun to just make copies of existing workshops and automate them.
Edit: Imagine this: a small custom bed and wood stockpile. The carpenter's shop can only take wood from this stockpile, and the beds can only be placed in this stockpile. Initially it's full of wood, but slowly the wood becomes replaced by beds and production stops, as no more wood can be put in the stockpile full of beds. You then construct a few beds, making space for an equal number of logs, which then get turned into beds.
In other words, you've just made a workshop that automatically makes a bed each time you place one in a room, keeping a constant number of beds in reserve.
Fantastic.