This seems to be a pretty sensitive topic lately, with the people that used this method of earning gil being the most upset (or only ones upset). I think it's pretty short-sighted when people say this change is going to kill the game economy. Yes, if you continue to remove ways to create gil in the game without adding new ways to do it, it will eventually kill the economy, but who here actually thinks this is the last change SE will ever make that influences the economy?
Fixing an economy doesn't happen overnight, and it seems SE was taking care of the first immediate problem, but when the next problem becomes apparent, I'm sure another change will come along. If the reduction of NPC value of these items truly "kills" the economy, maybe they'll reduce some of the gil sinks in the game to compensate. Honestly, I believe some of the recent changes show that they're trying to help the economy rather than ruining it, even if they don't seem to have as much of an effect on the economy.
The Fields of Valor feature giving gil is one example. Sure, a few hundred gil really doesn't mean much, but they could have just as easily charged players to use Training Manuals because what player doesn't want bonus experience, even if it costs a handful of gil?
The removal of Jeuno bazaar tax could also be a sign of SE trying to help the economy, although it really wont have more than a minor effect since players have always found ways to get around that, but maybe we'll see a reduction of Jeuno AH fees in the future as well?
Perhaps they're wanting to drain a certain amount of gil out of the economy until it reaches a point they're wanting? Maybe they want the gil rewards from quests and missions to actually be valuable. As it is now, most players would be lucky to buy a decent piece of equipment at the level they would need to complete certain missions. Gil rewards should actually be rewards, I think, not pocket change.
Really, I think the people that are really bothered by this change should relax and see where things go. Find other ways to make gil. I've never relied on NPCs for gil, and I'm an extremely casual player, I never have hours to devote to the game like some do. If this change really disrupts your playstyle that much, just quit.
I don't think it's really as big of a problem as some of you make it out to be, you're just probably upset that your quickest source of gil is gone. If it really was that much of a problem, you would have quit the game by now because it would be 'impossible' for you to earn the gil you need to play, and you wouldn't be discussing this on a forum for a game you don't play anymore.