This is just gameplay impressions, not stability or anything.  Mostly pacing related.

a) I think food should play a role in maintenance costs for troops.  You have more excess food, the cost of maintaining your army should go down (or lack of food should make it go up)  I think mounted troops it should depend on the mount also.

With a lot of gold, and not a lot of food, I was able to maintain a large number of troops- it should require a balance of gold/metal/food

While I support the overall reesource/economy  changes, I do think it needs some tweaking.  Without certain resources, I can see civs falling behind fast.

c) Questing/exploring for goodie huts: The High-level goodie huts need to be more powerful to make it worth researching.  It also seems back of spell knowledge isn't doing anything.