Make "No outline" the default for shapes
The current default, when adding shapes is same color outline. Most of us have to either reshape and make it as default shape, but we need to apply it to each presentation.
Let "No outline" be the default.
If you load a blank presentation, create and format a shape to your liking, make it the default, delete that shape, then save the new blank presentation as a template, all presentations made with that new template will recall the default shape properties you applied.