When the leading is set to Auto, and I click on the line-height icon + drag left, the increment of change is a decimal/float number, which means I have to drag SUUUPER far in order to make a decently sized change to the line-height.

Suggestion: Make the default increment = 1, unless the line-height is currently set to a decimal.

My hunch is that this will be easy to implement, because maybe Auto is currently 120.0% (float) in the backend, rather than 120% (integer).