There are still a couple quests which haven't been done yet :) For now... It is hard though, I will say that, even with optimized parties because we are essentially doing this on Hard Mode +. What I can say from experience is that buffs like barkskin and stuff aren't a luxury. They are absolutely 100% mandatory for the quests in their current balance, and with npc prices there is a really big difference in quest challenge and reward/sustainability. You can easily hit a point where you can't quest because you don't have buffs/healing, and can't get buffs/healing because you can't quest.
But it is still a work in progress! Once loot has been added, or some encounters tweaked, we'll be able to see what the bigger picture is like. At the moment though.... Buckle up buckaroo and get ready to score some bragging rights of "Yea I did all that stuff before it even had rewards!"
