I spent about 3 n a half hours googling with various keywords, and then read through this whole thread, but still can't find the mod... I originally found it on a mod list (i think it was one of those 'immersive' lists as well). I've been through almost all of the lists on the first post and I'm sure it's not there, or I just missed it =/ I downloaded it about six months ago and can't find the file, but I really want this mod...
From what I remember, it primarily added/changed almost all of the vanilla side quests. It added heaps more options (both in how to get the quests and how to finish them, and in conversations with the quest giver) and fleshed out a lot of the side quests and added more content to them, and added some new quests for areas that where bland/had no quests before. I'm fairly certain that it also added more conversation topics to npcs that where unique for towns etc, e.g town A, all the npcs have unique rumour topics about that town, but town B npcs would have different rumour topics. I'm not sure, but I think this mod might have also added a more immersive way to 'discover' the official quests.
It's really frustrating me that I can't find this mod, because I distinctly recall downloading it from tesnexus but I can't find it. If anyone could point me in the right direction I would really appreciate it ^_^