The one-click apply is an idea to automatically apply action, instead of selecting the plugins and clicking Apply button.
So how this could work?
1. You would need first to select an action from the menu, for example "Activate".
2. When you click on plugins from the list, instead of selecting them, this action will be immediatelly applied whenever you click on a plugin, meaning you can activate a plugin with just one click.
This option could also work for other actions like deactivate, update or delete.
There will be also a button switch that you can enable/disable the One-click mode.