High capacity energy/fluid/item transport- but only in an uninterrupted straight line.
Machines with replaceable parts- "pulveriser" as a GUI slot for the grinding wheel, sawmill as a sawblade.
Different grades of parts have different recipes, efficiencies, durabilities
lightweight parts are energy efficient, heavy parts use more energy, but process faster
upgraded parts process materials for greater returns [diamond sawblade yields 6 planks, iron gives 5]
If a part is removed before it breaks, the materials can be recycled.
Machines, engines ect with warmup and cooldown times.
Some kind of large crushing device to "reverse craft" stuff into its constituent dusts/scraps. (minetweaker style recipe adding?)
Ore->ore dust
Stone->Gravel
Wood->pulp/chips/sawdust
Metal block->9x metal dust
Piston->iron dust, wood pulp, redstone, 2x gravel
Tools/armour->Nx relevant dust [regardless of durability used]
TnT->explosion (why not?)
And that very funny moment some clumsy idiot falls in; resulting in a crushed inventory and some "mystery mince"