The only reason I would use paratroopers is to conquer annoying little Islands. Another idea is that if they land directly onto an enemy unit, they should be immediately destroyed.
With the new Web GL update the size of the unit on the map is so small that you can barely see what unit it is and sometimes can be hard to click on. My suggestion would be to increase the size of the unit on the map to make it easier on the eyes and more pleasant to look at.