Presentations haven't really changed that much over the years. The first presentation apps were designed to be used to make slides to transfer onto physical slides, before the invention of digital projectors, and still do much the same. Some efforts have been made in more recent times to improve this, but what we really need is a presentation editor that can handle multimedia from the beginning.
The first view is just a blank document, asking you to add media.
The second view is the add media dialogue, showing different types of media (photos, audio, video, webpages [with integrated webkit browser], new slide creation, slide [from existing slideshows], documents. and graphs/charts [with interactivity built in]).
The third view shows the import video dialogue, following on from the second dialogue. Options include importing from your own computer, from the web (e.g. YouTube) or from a video stream (e.g. a webcam). Similar options would be available for each of the media types, except create slide, which have theme options and slide templates.
The fourth view shows what it looks like when several things have been added. The left hand slide is a normal slide, the middle a video and the right hand side a photo. Next to the slide name is the transition options (blue glowing indicating it has had a slide transition added) and slide options.
Made in Inkscape 0.48 using the eGTK mockup kit and elementary icons.