Some ideas

[imcx]

Here's some ideas I gladly see in the game:

Music (partially mentioned in this this thread) based on the situation - weather, disaster.

More disasters (in parenthesis presented the suggested task force able to tackle the disaster or stop it from spreading):

- floods (police+military+fire) and
- drought - water shortage (retention water towers) + higher risk of fire warning (fire)

should come as an effect of rain or lack thereof. One could build water towers for retention, but not production, so only pumps produce water initially.

- riots (fire+police+military) , caused by lack of police, high taxes, lack of jobs (satisfy industrial/commercial demand).

Since I think year seasons are worth implementing, music could also change based on those different seasons based on in-game month.

Drought and flood wouldn't happen in winter but water shortage and fire can.

More fires in commercial and industrial zones without police coverage, even on fire covered areas.

So, to sum up:

1) different weather + graphics (snow/rain/sunshine/rain) for different year season, based on in-game mode (adjustable for northern/southern hemisphere)
2) more naturally occurring disasters in flow with weather system and gameplay (rain=flood; drought=fire, water shortage; residential demand satisfied, high commercial & industrial demand - lack of police - lack of fire - high taxes=riots)
3) different music for different weather (ideally 3 tunes for each of, making it 12 tunes + 4 for different disasters - fire, flood, drought, riot)