DarkSchneider
King
That's no more realistic, not even in 2010. In fact I'm pretty sure that going to war and annexing cities causing unhappiness is more realistic than equalizing the viability of all settlement locations.
I think the War Weariness in Civ IV was already pretty much perfect. As for global food, a number of large, important US cities are built on deserts, something that would not be possible without national food.
The most realistic way to model it in the game would be effects based on the shortest trade route between cities. Cities with large food surpluses would gift them to cities with less food.