So on minecraft, we all love making the small hidden bat caves, here's my idea for adding something more realistic like minecraft piston and stuff....
Pistons: you can craft one with wood and stone
Sticky pistons: wood, stone and slime as it's sticky
Switches: stick and stone/wood
Pressure plates: stone slab, can also make from bricks etc
Iron wire: this is a nice twist I think, it is realistic as it's conductive, so it would work similar in real life
How they link up
It would be cool if it worked just like minecraft and Redstone dust, you flip a switch, it travels along wire if a wire is next to it, and then if there's a piston or door or trapdoor, it opens/activates it. Something I really wanted for a long time though, pressure plates that open doors, you stand on them, does the same as a user clicking the door, when you leave it door closes, it would be awesome as you wouldn't need to close doors all the time, and if you wanted it open permanently, override it with a switch.
I believe that both Pistons have a redstone dust in their crafting table as well, but they, they should start off with the very simple redstone tools(like buttons,levers, pressure plates,etc.), and then move upwards and add the more complex redstone tools(like the things added in the Redstone Update from MineCraft, like hoppers,droppers, daylight censors,etc.)later.