Slightly related: I feel it's worth spreading the word about yabai [1], a tiling window manager for MacOs. I've been using it for >1 year, to get an i3 like experience, and find that it makes using MacOs very pleasant.
Issues in the article are somewhat addressed:
> Focus Follow Mouse
Can do this with yabai
> Always on top windows
Can do this with yabai
> Window snapping
Can do this with yabai
The way I use it: I have 9 desktops, and can switch between them via the keyboard (ctrl+<desktop_number>). Can move apps from one desktop to another via keyboard commands. Apps are automatically resized to fit. Can move apps around on screen via keyboard commands.