This though came to mind a while ago and figured I'd throw it here. it relates to both DOL/DOH scrips atm and I feel it could liven the system.
As it stands now it's rather stagnant as in it's a system purely done through one window, you give items to x person and then you get reward to turn in for stuff. They could better integrate the system if you could unlock clients by doing the DOH/DOL questline which would give purpose to complete those.
Let's say you hit 60 and your options for turn ins are based on only having Rowena as a client and her "speciality" is all around meaning she will ask for something from everything but she doesn't give any perks/boost for turning in with her, aka she's cheap.
Then say you complete Carpenter quest, you unlock that person as a client and he ask for Carpenter, Blacksmith, Leathercraft and Botanist items. Each day he'll ask for 2/4 and by turning in items to him you increase your reputation with that NPC and said client will offer you more as well as ask for higher quality collectible items.
In the end instead of just having Rowena as a person to turn in to you would have 13 people in total by going through all the DOL/DOH quest each asking for 4 different types of DOL/DOH that would change daily. It would liven up the system more, allow more options for turn ins and it could even reward players for focusing on certain clients since they would offer larger rewards for turn ins.
Again just a thought that popped in my head, but when I think about the collectible system it really lacks in how "alive" it feels, it doesn't really feel like you are being useful to the NPCs around you just Rowena herself and it takes away from what the collectible system could be, which should be about bringing to life the NPCs around you and offering your help to them by giving them the items/gathered items they need.