give workers the ability to built steps or terraces so you can irrigate hills...its been done for a LONG time now...

im not talking complete terraforming like in CIV II where you can keep changing the terrain until you get what you want.

for hills remove shields if you "irrigate" the hill. that way you get one or the other, something to balance it out.

maybe two kinds of farming similar to CIV II? link the second, more effecient form of farming to motorized transportation maybe? maybe that would make things too complex?

Using the editor, you can make hills available to be irrigated.

Hills were irrigatable in CivII. I always wondered why they took that option away.