I do a fair amount of public speaking, to classes, community groups, administrative departments, you name it. I've been using presentation software since before there was a PowerPoint. (Anyone else remember Adobe (neé Aldus) Persuasion?) Typical presentation software is great for topical presentations which define an area of interest and then delve down into it. Their operating model is that of the classic outline: break the overall topic into parts, then break each of those down into its components, then say something about each component, show how the pieces fit back together, and ask "are there any questions?"
Typical software is also adequate for presenting simple comparisons and contrasts. Do a simple decomposition of one entity in Column A, of the other in Column B, make your points about significant similarities or differences, and ask "are there any questions?"
But typical presentation software runs out of room if you try to compare/contrast three entities. Yes, you can probably achieve the task at hand. Maybe the audience will be able to follow what you're saying. But no, the software doesn't really make the task easier. Try it, and you may well find yourself wishing you had a whiteboard. Or a blackboard. Or even a flip chart and markers.
Where typical presentation software is really unhelpful is when your point is to draw connections (real or potential) among aspects or elements of entities which, in the audience's mind, belong in functionally separate realms. Not, perhaps, as separate as the tensile strength of stainless steel and whether "The Adventures of Huckleberry Finn" is racist, but entities which audience members typically compartmentalize apart from one another.
Take a case in point: curricular matter is taught in classes of various forms; classes make up courses offered by various academic departments; the departments take advantage of support services provided within schools and colleges; the classes generally take place within rooms and buildings operated by other support organizations (departments of the university); the ways in which curriculum is taught, classes are offered and housed, and academic departments are administered determines (in aggregate) much of the operational profile (resource demand, services provided, waste produced) of the institution; and the very complexity of institutional operation at all levels offers a plethora of opportunities for students to observe, measure, experiment and better understand much of what they study.
Whether the previous jumble of thought identifies opportunities which are rare or universal, the understanding (or misunderstanding) that underlies it can't be well presented within the linear, either/or capabilities of typical presentation software. (Or if it can, I haven't yet figured out how to make that happen.)
Some time ago, I was introduced by some grad students to prezi, which I think of as "atypical" presentation software. Rather than operating on the model of an outline or a deck of slides, prezi provides its users with a broad canvas upon which to describe whatever they're talking about. The audience's focus is moved around the canvas. Point of view zooms in and out. Specific data or concepts emerge from various contexts, both expected and otherwise. Connections are depicted visually, rather than being described verbally. Thus, relationships can be presented in more intuitive -- less definitional -- terms. Associations can emerge, Compartmentalized thinking is challenged (or certainly can be).
I'm not nearly as adept at creating presentations in prezi as I am in PowerPoint. And there may well be other "atypical" presentation tools out there which turn out to be far better for my purposes. But it strikes me that the type of non-linear, non-compartmentalized thinking and discourse that prezi supports is critical to any meaningful understanding of sustainability issues and strategies. And that the strictures embodied in traditional slide-deck thinking are part of what got us all into this mess.