I have noticed two usability issues with the window preview behavior. This is with "Show window previews on hover" enabled and click action set to "Toggle single/preview multiple" which most closely attempts to mimic a Windows 10 desktop.
When hovering over an application icon that has multiple windows open, the window preview will display as expected, but clicking the icon causes the preview to disappear. This is a problem if the user's intent is to move the mouse to the icon and click to open the window picker. If they click too slowly, it will cause the preview to appear from the hover, only to disappear on the mouse click, forcing the user to click again to reopen it. The Windows 10 behavior is more user friendly in that a mouse click does not close the preview but rather switches the the preview mode from a tooltip like mode to a menu like mode, which leads to the second issue.
If an application has multiple windows, and the user clicks the icon to open the window preview/picker, it exhibits tooltip like behavior of closing automatically when the mouse moves out of the preview area. This is a usability issue because if a user is inaccurate with the mouse and overshoots their intended target, the preview will close, forcing the user to move the mouse back to the icon and potentially reclicking to open the preview again, if the enable on hover option is not selected. Across OSes menus which require a click to open remain open regardless of mouse position until the user clicks again so that the user does not need to be super accurate with their mouse movement.
I hope this is helpful. Zorin is otherwise one of the easiest Linux distros to use and would like to see it and the Linux desktop itself be successful.