Well that is a rather impressive list there, so lets get to work judjng each and every item to its own merits shall we!
Steam: Great idea! Full support for this.
Other Gasses: Once again something great that I want to see made more avaliable and realistic in the raws atleast.
Electricity: I shall pass on this one. Not something I want to see.
Conservation of Energy: Without question I want this. If it makes the game harder, then it makes the game more fun.
Gravity damage: Capital thought! Dropping bars on lead on incomming hoards is something I can relate to.
Moving Objects and Inertia: IF this can be done without eating FPS, go right ahead!
Moving and Rotating Walls: See above.
Tech Tree: Not realy. I think DF is more about application then invention. That is finding a new use for already existing things. Using things in a new and awesome way, then making new things.
Fluid Dynamics: YES! AND DOUBLE YES! To add to this.
+Add water and lava to the raws.
+Make all liquids able to fill a x/7 space, rather then just form puddles.
+Allow us to edit in new reactions between liiquids rather then just water + magma = obsidian + steam.
Fire: Yes, especialy if we get flamable gas.
Optics: Maybe later on, not as a high priorty right now though.
Construction: If concrete is the only thing to be suggested here, I shall pass over this as not detailed enough. I want to see more here.
Vehicles: No need to comment on whats planned, apart from I hope there is a lot of modifiable things in the raws.
Signal Propagation Delay: Don't we already have thi for some things?
Steam Turbine: Yes, even more so if we had more uses for rotating power.
Kinetic Battery: I think this is best left to player design. Like lava flood traps, they wouldn't be something we select from a menu, but rather something we build with our own hands, so to speek.
Chemical Battery: See above, also see Fluid Dynamics and suggested addition of reactions.
Capstan: We sort of already have this in the pump stack (Come to think of it, high water also acts as a Kinetic Battery) so once again, see above.
Furnace/Incinerator: I know we already have this! And the second one can be modded in, so not something you should ask toady for, rather the modding forum.
Combustion/Piston Engine: This would be too fun to build ourselves, even more so using the steam turbine and fire and water. Don't just let us be lazy and plonk one down.
Pipes: I have been making these for ages. Just halls that you don't let dwarfs into.
Waterproof Axle Section: I would support or not support this depending on how it was implmented.
Belts: Yes.
Heavy Doors: VERY YES!
Clocks: Maybe no. Let us have our fun building our own.
Bells: Full support.
Rock Grinders: Makes a lot more sence then using a bridge.
Workshops: I'm not sure what your asking here. We have these don't we?
Fans: Ok, if there is some sort of application.
Mechanical Lifts: YES!
Power Drills: I'm saying no.
Dwarf Trainers: Na, modders already do this and I'm not a big fan myself.
Vertical Pump: YES!
Spiggot: Wouldn't a flood gate do?
Pressure Equalizer: If there was no way for players to build there own, then ok.
Internal: See pipe.
Misters: I have been building these too for a long time.
Dams: How do you expect to build these from a menu? Realy? Apart from that, building already.
Tripwires: New trigger mechinisem for things? Isn't it similar to the pressure plate?
Cycling/Alternating device: Repeaters are easy to build as it is.
Fuses: I'm thinking the best implication of this would be to have something that let off flames a set time after a dwarf has lit it, meaning said dwarf would have to run for hes life. What could fit DF more?
Delay Boxes:
And I think you can already do this with water, flood gates and pressure pads.
Temperature Sensor: I would say no. If you want a temperature senser, have a goblin stand on a pressure pad. When it gets so hot or cold that he dies, the pressure pad is relesed.
Pressure Plates: Yes to all!
Weapon Traps: Yes to all EXEPT
+Make them require power: Yes for some traps, not others. A stone does not need power to fall.
Stone Traps: Yes
Drawbridge: Yes
Mechanisms: Yes to all bar make only out of metal. Make BETTER ones out of metal, but stone would also work.
+To add, make signal delay dependent on the distance from the trigger to the event and the quality of the gears. Metal gears are faster then stone ones,
Levers: Yes.
Traps: yes
Siege Engines: Yes
General Devices: YES
Small Traps: Sure, why not.
Mine Carts & Conveyor Belts: Super big yes.
Clocks: See clocks before.
Alarms & Bells: We have been over this you know.
Logical Operators: You can already do this.
Ability to hide floodgates/doors: Would be nice.
Small Mechanisms: With the things I have said I would like, I don't see how this would be needed.
Sound Pipes: Naaaaaaaa.