Dynamic Weather

Dynamic weather to me would be incredible to have. Also realistic effects on a city based on current weather events (for instance, lightning strikes have a chance of causing a fire).

Also the weather would change depending on location. Cities near an ocean would be vulnerable to cyclones, relatively flat areas would experience tornadoes (real looking ones, not the excuse for tornadoes SC4 has) and river areas would flood more easily.

That would be great! I especially like your idea of weather changing depending on location. If you are in the desert, it probably shouldn't rain everyday.