Wonderful post! I too was surprised at the lack of bugs from Oasis, just shows the quality of developer you are I think!
As for the 6-8 hours in statistic, I think on paper there is a progressive and linear ramp in difficulty with the mobs in the world, but these mobs are scattered throughout the world. There's snakes and wolves next to Sackle for instance. I don't think that is bad, I think that part of what makes Tales of Yore what it is, but if you were to add more content, I would look at this point in progression and perhaps funnel players into some kind of linear progress if they are stuck. This could be as easy as making a Game Guide for instance, which goes through quests in an order that is most linear.