You know I think this is something of a first. Most MMOs always seem to experience some kind of massive inflation issues with the economy. I've never seen one suffering the opposite before. I highly doubt that the devs aren't aware of this. To some extent I would argue it is deliberate as it allows them to tweak things up rather than down, and allows them to control inflation much better.

In my opinion the easiest fix would be to have the 'first time' bonuses on instances reset every so often. Most low level dungeons and basically ALL of the guildhests are never run more than once for those first time bonuses. If they simply had all of those reset say... once a week? You would not only have a viable (but controllable) means of making money, but you would also encourage players to revisit old content which would reduce those insane queue times in the duty finder.