Some things may happen as the time passes. This will bring a lot of diversity in the world, relatively cheaply.
Also some events, that not only alter the environment (e.g. spawn rate), but also those that require some "immediate" action on the player side,
I like this idea a lot and thought about it the past few days.
We could do something like a weather that changes daily and has only as an effect on the overworld.
For grassland weather states could be:
sunny - everything is normal
rainy - free tiles next to ponds an be flooded, agriculture will grow faster
foggy - your view radius is smaller
dry - aggriculture can wither, ponds will shrink
sandstorme - like foggy in grassland
heat(will be the most time) - everything normal
flood(very rare) - the river will grow temporary and make the bridges unpasseble
Next there could be events that effect the whole game
strange vibes inside the ether - magic has a higher chance to fail at this days
bloodmoon - monsters are strong
lucky day - bonus on luck
Finally we could have rare events that only effect one map.
a stanger occurres
The other events that require player action should be quests you can obtain from NPCs in sanctuary.
I would say we should put random events as a goal on our list for version 2.4.