Supply Lines

I think it would be good to see the option to create a building type that would trigger a unit to come from offscreen, dock/land with structure, offload credits, then leave.
In C&C: Generals, the American side had an option like this, the Supply Drop Zone.
Transport unit could be a helicopter or a ship or even a chrono-truck, depending on side, map, etc...

This would give an alternative to the standard "ore harvester" approach, while not creating the imbalances created by arbitrary oil derrick construction.

Additionally, it could create a new and more realistic dimension of gameplay by making the players protect their supply lines. This would come in handy in longer games where the ore is running out, or on maps that have no ore.