The difficulty is already being smoothed out: the curve on the four regional dungeons, Venture Cave and Den of Danger will be a little more generous with the next update, and we're busy testing out a bunch of quests to apply to these areas so that players have another way to build up strength and resources in the long term.
You won't see them just yet, but quite a few quests actually have item rewards which increase the shop pool (if you've unlocked THOSE yet) and give you some powerful tools to put into your adventuring locker as well.
... and yeah, we've taken note of the Glowing Guardian "humility exploit". Bye bye, repeatable boon casting.
He should be useful enough even without that, we think.