So I was thinking of a cool thing that could be done with skill trees that ties in with the slightly randomized nature of stats when crafting stuff, and I came up with this:
When mining/logging/etc you have a small chance to get an (item)+1
This chance increases with the related skill tree, and the difficulty of the world
When crafting, you have a slight chance of increasing the level of an item, so from +0 to +1, +1 to +2, etc.
When crafting a tool with +1… materials, the tool’s base stats will be slightly higher, stacks when using multiple +1… materials.
The gathering and crafting skill trees could have 2 specialization paths, one increases the chance of gathering/crafting +1… blocks, the other increases the speed of gathering/crafting.
This would lead to a constant demand for rare resources, as +1 blocks would be fairly rare, but provide good bonuses like increased durability, faster speed, more damage, etc.