Quests are very difficult to set up. Each step has to be set up, so that the NPCs, triggers, monsters, etc you interact with know where you are in the quest and act appropriately. Even something as simple as the doll quest took about 4 hours of work to set up and debug.
Now this doesn't mean I won't do quests. I would love to add more complexity, but I need details. I think I mentioned that somewhere else. The idea is only the starting point.
Beholder Item Quest
Step 0 - Quest not started
Step 1 - NPC asks for help (accept or decline). If declined, go to step 8.
Step 2 - Monster killed, item found, etc.
Step 3 - NPC rewards first piece of two part beholder item. Refers to next NPC in quest.
Step 4 - NPC 2 gives second task.
Step 5 - Second task completed.
Step 6 - NPC 2 give reward (second part of beholder item). Tells you to talk to Darla.
Step 7 - Darla combines items to make the beholder immunity item. Quest completed
Step 8 - Quest declined at any point...failure step.
This is just an example, and I left a lot of specifics out. Let's say you're at step 1. I would need to set up triggers to spawn monsters, create placeables, whatever at the appropriate points so that you can get the first items. One of the subquests may be to find an injured person in the dungeon and heal them.
Anyway, that's the kind of detailed information I need to set up a quest. So, if you have step by step concepts for something you want to see in the module, post them here.