White space is a good thing in design. It makes text breathe, the whole page looks calmer somehow.
This applies to business presentations as well. Cut text that is not required, make images as big as possible, and your slide starts to look like a well-designed ad on a billboard.
However, in some cases, a business presentation slide is not meant to be a fashion ad. Think of the sales target data for the next quarter, or the new IT system architecture that you need to get approved. What I often see in SlideMagic is a “left over battlefield” with the final product of a complex table or system diagram. After many iterations it finally looks like it should look and everyone agrees to it.
In the process, the designer forgot to clean up, and remove rows and columns that are no longer needed. In SlideMagic, you can get rid of them with a few clicks and your entire diagram or table will scale up instantly, in the right proportions.
Yes, you gave up some white space around the edges, but overall the chart is more practical. To make things calmer, consider cleaning up data and text in the cells of your diagram instead.