We have two graveyards in the game right now. Maybe next year you could make it so that the lower Necropolis would be for levels 1 to 12 with spawns that would work for them. No one over 12 would get anything but negative levels being in it. This would not stop anyone from doing the raid, we all use the farshifter anyway.

Keep the current one for 13 and higher but take out the low levels spawns. Put in a few rare spawns like ghostly beholders and the such.

Over all I have had a good time and have enjoyed this event.