Personally I find digging peat in swamps to be an easier source of “cheap fuel” than charcoal from grassland fires (since you have to wait on fires to burn out and not always get charcoal), and I seem to always be able to find plenty of swamps around. So I never found charcoal to be overly easy since peat is even easier. Destroying items via campfires is also supposedly in the works.
I think there are some future plans for all that animal fat … hopefully leaves too since I have mountains of those as well :p
The upcoming new version is supposed to be completely revamping iron items, with pig iron used for poor iron items (with the exact same stats as current iron) and iron items upgraded to a new higher tier. I think there is also plans for a steel tier after that too. Much tougher mobs (demons, lizardmen, mages, stuff with range attacks etc) are in the plans though I don’t know if he plans to link any of them direct to treasures. Those might not be in the next update though, maybe Vaughn will tell more soon …
I am pretty sure that conditions for “winning” the game are getting tougher as we progress to future versions (not everyone though is chasing after ‘winning’ though so there is some more sandboxy stuff too with agriculture , beekeeping & spinning wheels, lots of construction, other stuff to keep players busy with projects ..)
I think what we have seen so far ingame is pretty much just the tip of the iceberg for what is ahead ^_^