Also from a rp point of view it would be kinda awesome.... especially for a vampire character during the polar night period!!!! 30 Days of Night any one? :chaos:
If there are 30 days of night for a vampire to roam whenever he wants, then that means there will also be 30 days of sun that will kill the vampire. If they have 30 days of sun, then EVERYBODY that wants to be a vampire will complain and freak out.
For the sake of our sanity, I think they shouldn't have 30 game-days of night/day, but maybe extend the time a little bit, so the amount of sun and moon will vary from 8-16 hours of each. That will make it so it is noticable, but won't cause people to freak out about there not being night or day.
TL;DR
I think they should vary the time a little, but not as extreme as having 30 days or night/day. Maybe just make it so the length of day and night change as the seasons progress.