I'd like to see indications of the land being altered by monsters, magic, men and mayhem.
Like spider webs becoming visible in the trees, as a spider colony grows more populous. On the world map, player notices webs atop a few trees in a nearby forest. Overtime the webs thicken and the canopy expands. The threat grows. If you leave it over-long, the forest dies and the spiders mass migrate to new homes. Six groups of ravenous spiders, each lead by a monstrous sister queen; walking about the land, preying on people and whole towns, looking for suitable nesting and prey sites. To begin the process anew, but many times over, if not stopped.
Mage casts Corrupt Land. Maintains enchantment for long time. Leaf and limb wilt and sag. Unsightly, and atmospherically unpleasant to be in; but not a threat to health.. yet. Though the fauna begin to flee, as the flora loses fertility. Can be settled, but yields little. Corruption germinates over time. Eventually the flora of that land, is overrun by genetically corrupted versions of the original. A living rot. Every cell filling with an infectious ooze. Swelling in the humidity and heat of the fetid waste, to randomly burst like an epic'ly popped pimple. Spraying it's nasty innards, to spread a corrupted infection upon anything unfortunate enough to be within the blast radius. A dangerous place to be (like the "Blight" in WOT). Units lose HP each turn. Land cannot be settled. By day the rot corrupts flesh and soul. The night is prowled by corrupted distortions of creatures that have died within.
It is widely said the dead walk there. Nay, those monstrosities have never known live. They are corrupted copies of the dead. Animated to prowl the night, extinguishing all life within the corruption. Come dawn they collapse to a pile of rotted mush. To rise again at night, once and again, eternal. Each night further corrupting the genetic design. Morphing the monsters to designs beyond imagination.
(Originally a Civ4 mod thought, originating from a D&D campaign I crafted, but was never played. Big concepts such as subterranean maps, where not possible in Civ4. Can it be done in E:FE? For mods? Sometimes I wonder if the mod is better as it's own game. Many mechanic changes such as settlers settling camps vs cities. Player grows camp over time to become farmstead, fort, town, city, +. Different decisions, resulting in different types of settlements over time. From garrisoned fort to self-sustained castle. From agricultural towns exporting food, to mining towns and trade hubs, and governing and science cities, and sorcery and.. So then I wonder how one goes about presenting Stardock with an idea for a game to build using it's new engine.)
The draining of swamps and magicaly morphing them to develop into enchanted meadow islands, among clear water pools and crystal streams. A 'matured' mystical meadow attracts nature sprites or some such (Lord Xia's Ponies?). Or gives Life Mana.
Upwelling a spring in the desert, to become Oasis, ringed by a band of barren desert.
A flush of rare spring flowers, on the site of an epic battle, which actually happened in game.
A spell to raise skeletons from an ancient battlefield.
Regrowth after a wildfire. Ruins decayed over time.
The planting of forests, orchards, vineyards.
Lands growing haunted, shades emerging.
But these things aren't immediately gratified. They occur over time. Player gets to see change over time. And player faces more complexity in decision making: Long term investments vs short yield. They see their decisions are reflected in the game world. A living world where Orchards are planted, then mature over time before becoming fruitful. Where magic can crack the surface of the earth to call forth the magma, and man can irrigate desert to fertile bread basket; but mage and man merely provoke nature to do, in it's own time, what it will and how. I'd like to see it in game. How about you?