Copy animations from one shape to multiple shapes with a click of a single button or copy animations from/to library to
shapes in the presentation and vice versa. http://www.mvps.org/skp/ac/
Other than the add-ins mentioned, try applying all animations to AutoShapes
or text boxes. For example if you had a picture inside a rectangle (using an
AutoShape with picture fill), you could just change the picture fill and the
animation would work.
You could even change the AutoShape using the Draw | Change AutoShape option
in the Drawing toolbar.