Simple video management and processing tool for Mac?
One option is DaVinci Resolve, it is free, but requires 16 GB of RAM and the largest GPU available for the machine. 

Requirements:



if you're looking for something on the simpler side, and free I may add, GoPro Studio is also available for free, but with some limitations, such as with filters and effects that must be rendered in another software before being imported into the software itself.