I'm new to the game, but as far as I experienced:
1 - the dirt stacks in your inventory. I've read somewhere that dirt was "automatically placed" on the ground around you, and a "mountain" was created without you want it. So, I think dirt being stackable upon digging is a good idea.
2 - Maybe the construcion blocks, wooden logs and bamboo logs could have a bigger stack? Like, i'm going out to cut some trees and get as many logs I can, so I can go back to "my house area" and begin it's contruction (or keep it's consctrution o bigger scale).
3 - For the weapons, if they are in your inventory, it's logic it count for the inventory space as the other items count
4 - Inventory items ordered by alphabet anything else could be good for someone. Well, on any game that has a inventory, the player wants to arrange it on is own taste (usually weapons together, food, clothes, etc). You know what I mean?
