Nightly raid? No thank you. Survival in this game is stressful enough on the player as it is; a nightly raid would become a chore that many would not want to even deal with, thus turn them away from the game entirely. That design choice would be pretty bad for business.

I think a more sensible solution would be to add a warning before a raid was starting. Regardless of the raid, a warning (5 minutes, maybe?) telling the player that "Something is stirring near by.." before the actual raid happened.

At least then you'd have time to stop what you were doing, eat and repair gear, and maybe even distance yourself from your structures a bit before having Skeletons, Trolls, Draugr, or Fulings up your ass from every direction at the drop of a dime.