Zoom using mouse wheel during world exploration to very quickly adapt to current task, e.g. zoom in to do some precise mining or zoom out to engage in a sudden battle. A choice could be added to settings (scrollwheel = hotbar / zoom).
Reasoning
I'm on PC version and mouse wheel seems to be hardcoded to some very useful functions like menu scrolling. I don't think it's possible to manually set it up for zooming. Precision work comes often in this game and zooming using keys is suboptimal, especially while mouse wheel sits there unused. Personally I find cycling hotbar with the wheel too inaccurate, especially in the heat of a battle. It can even lead to death if I move the wheel accidentally.
Reasoning
I'm on PC version and mouse wheel seems to be hardcoded to some very useful functions like menu scrolling. I don't think it's possible to manually set it up for zooming. Precision work comes often in this game and zooming using keys is suboptimal, especially while mouse wheel sits there unused. Personally I find cycling hotbar with the wheel too inaccurate, especially in the heat of a battle. It can even lead to death if I move the wheel accidentally.