A few Minecart related ideas to match the new caves and cliffs:
- Couplers: Crafted using chain and iron, couplers allow players to connect minecarts together. Right click on a minecart and an adjacent cart to connect them. Shift right click or destroy a cart to get the coupler back.
- Minecart with Smoker and Minecart with Blast Furnace: The former pulls less but goes faster, the latter pulls more but is slower.
- Copper Powered Rails: unlike standard powered rails, copper rails provide less speed and cannot be deactivated.
- Chain Rail: Chain rails can be powered with redstone to move minecarts uphill cheaply and slowly, simply replacing the stick in the rail recipe with a chain. Unlike powered rails, an unpowered chain rail will not stop a cart.
- Cross Junction: A quality of life item minecarts have sorely needed since day one, cross junctions are crafted with 4 rails and a plank to make a rail that can be crossed in all 4 cardinal directions.
-Railway Sign: Crafted with a bell, a sign, two lanterns, and an iron ingot, railway signs can be powered to light up and chime. The noise drives passive and hostile mobs away a small distance so as to serve a small function in single player, but in a multiplayer setting this is just a cute addition to a rail system that may cut through a town or over land
While I'm sure it would all be a lot of work and might push the update back a ways, minecarts haven't really gotten a lot of love, and this update seems like a fine time for it.