What if we could automate alteration? Adjust blocks like pistons and repeaters without having to touch them? Let me suggest The Modifier.
The modifier would be a metallic mechanical block with a gear pattern, to signify generic steampunky complexity.
Each time it receives a redstone charge, it changes blocks its touching that have multiple settings or possible positions. It would make one change instantly, then power would have to be turned off and restored to cause another change.
Non-extended pistons are rotated, changing to a different one of its 6 possible directions. The order it would follow when rotating is N, Up, W, S, Down, E, N, Up, etc. so by controlling the number of times the modifier is turned on you can select precisely which way the piston is facing.
Dispensers, Doors, and Stairs would rotate through their 4 directions
Fence gates would cycle through their 2 directions.
Repeaters would cycle through their delay settings.
Note blocks cycle through their notes.
Using this you could create a variety of more complex machines.
Perhaps it could also adjust some other blocks as well, if I've forgotten anything. For example it could also make cosmetic changes like altering which way a dispenser is facing, and could also change the direction rail is facing.
Hey, what if modifiers could also flip switches on and off? You could use it to automatically reset switches in a big machine.
You'd have to make sure the modifier isn't touching the switch when it's flipped on though, or it would instantly turn itself back off. So you'd use some kind of system that uses pistons to push a modifier next to the switch and powers the modifier when it's the right time.
It'd be easy to do things like make a machine that flips off all its switches every 5 minutes.