it wouldnt neccessarily create more lag, its just clientside, and it can be easily done with an overlaid white image with seteffectmode 2 and adjusted to screensize and the imgcolors would vary depending on daytime, its a lot less laggy than snow
the interactivity would grow so nice, and fireworks would make sense if its darker
when it gets dark, lanterns go on, and so on, thats all doable and easy with classes and servervars
rufus' thread is really nice too
probably an announcement before it gets dark and a PK zone so newbies can hide xd