I am uploading lots of slides now to SlideMagic everyday. Where possible, I create multiple layouts of slides, often depending on the underlying image I use. For example, see the juggler below.
There are lots of degrees of freedom:
Image in a frame, or bleeding of the the page
Line up text with the balls, or not
Different colour options
As a SlideMagic user, you can pick one of these basic layouts and add or subtract boxes easily without messing up the overall of the slide.
Try it out for yourself, the search for juggler slides is here. For the moment, I have made access to the entire slide database from within the desktop app free, so you can experiment with presentations in .magic format. PowerPoint conversion and/or downloads require a pro subscription.