The new icon option only affects the taskbar if you have the taskbar configured to "never group" (not the default Windows behavior), in which case it should help you tell one window from another (if they have different folder icons) and be useful, if you give it a chance. Up to you which you use, though, of course!
The option to revert back to the old behavior was mentioned directly in the release notes, as the third bullet point. If you install an update and want to turn off a new feature, the info on how to do so will often be there already.