For those that aren't engineers (I'm not one), an Archimedes' Screw is an old method of pumping water up from below. It is made up of a tube and a spiral that turns and drains out the water, or oil or anything else that's not structurally solid.
Technically speaking, the screwpumps in DF are Archimedes' Screws (probably). What I suggest is a new type of pump to replace the pumpstack, mainly for simplicity. The pump would be 1 square, and would bring liquids from below into the pump itself. The top pump would be below a screwpump, to bring the liquids out of the pipe below and to the desired direction, and the power requirements would be 10 per pipe section. A dwarf pump operator would need to work harder for taller pumps; I'm thinking a limit of 1 z level per skill level of the operator, maybe less. Each Archimedes' Screw would require 1 giant corkscrew, 1 giant pipe section, and 1 block; possibly 1 mechanism as punishment for trying to cut corners of something.
Some more minor stuff I'd like; power requirements less for better designed buildings made with higher quality components. Not necessary, but it's nice to see that your architect actually has SOME use in your fortress. Like, 1/2 power for masterfully designed pumps made with masterfully crafted mechanisms and pipes, and your windmills/watermills could produce somewhat more power for being masterfully designed.
The ability to toggle "magma safe only" when placing things you expect to come into contact with magma. So, when selecting what to include in your screwpipe, it would only list the stone blocks that are magma safe. Maybe it would require a manager with some architectural background (e.g., Adequate Building Designer) to enable it.
Dwarven music halls. Basically a garden of sorts. A new room built from large instruments like dwarven pipe organs or harpsichords (pianos didn't exist until the 19th century so those aren't allowed). Dwarves with the musicality personality may hang out there when on break and play some instruments and get happy thoughts for "was able to express self musically", and dwarves in the vicinity can get thoughts for "heard a stirring ballad".