Given that these quests are open to everyone, they get played more than any other quests.
Some of the older ones could do with slight revamps. Maybe the addition of some special creatures (like some added recently). I know that vampire bats definitely need an appearence in the first 5 missions of the necropolis, especially the bloody crypt and the church and the cult . (even though this isnt f2p)
Rest for the restless for example, the old bone filled sewer could be improved by having a different looking skeleton (he's meant to be powerful) at the end. Possibly even a blackbone.
Do we ever get to meet who made him anyway? wheres the necromancer?