Weather and Seasons
Day time is always bright and sunny, this incentivizes players to play with shortened day durations.
To lessen the desire for shortened days, a weather system would be a good solution.
For example, there may be the chance for rain storms resulting in large cloud coverage.
There could even be negative side-effects, such as thunderstorms making bat form more cumbersome to use.
In addition to daily weather, there could be seasons which dynamically adjust how long the sun is out. Seasons could also buff certain spell categories. For example, winter would make all Frost spells X% stronger. Summer would do the same for Blood spells, and so on.