suggestion

[NateMarrocco]

The app would be the fastest switcher in the world if each window had a key assigned to it like in the vimium browser extension and then the desired window could be selected by pressing the corresponding key. This would dramatically reduce the number of key presses necessary to switch between windows from n in worst case to a constant 2.

[1j01]

This window switcher piggybacks on the native Windows window switcher, so I don't see a practical way to implement this.

Sounds like a great idea for UI, but maybe not a good fit for this project.
That said, the app switcher in this project is totally custom, and I could see supporting two window switchers that you can choose between in the installer. And the app switcher might be a decent basis for a new custom window switcher. (Ideally they could share some code and both support the numbered switching.)