I am not sure if you ignore what I am saying or if you disagree: Quest design is difficult and takes a lot of work for something that will outstay it's welcome rather quickly. I for one don't care for quests after the first time. I can endure them a few more times but after doing them for years on end I just want to puke for the lack of impact of uncovering yet another EPIC conspiracy. Quests are pointless if they don't have a lasting impact and they probably never will because you'd need some seriously sick AI that designs them and incorporates their outcome into the game world. I guess that same AI would much sooner wipe the human race from the face of the earth.
Quests are content but not the right kind for the game itself and for the man power behind them. Missions are fine because they don't pretend to have any lasting impact. They are the busy work that is short enough without the fluff. That doesn't mean we could use more mission variety... and they could also be somewhat more limited (with higher rewards) based on how many are done in a given time... but that's just game design flavor.
Again: Content is hard and time consuming. Fixing shit is maybe not nearly as much fun but 'shit' is what most of the nc population is doing for most of its time. Focus on that! Use your resources wisely.