Too many training sessions are (in my opinion) still built around a slide deck. Even if your slides are visually appealing, minimal in their use of text and useful, they are still very limited in terms of explaining how the session should run. They can only ever be a) a visual aid for the delegates, and b) a prompt for the facilitator.
Great training sessions are designed in detail. This means having a detailed session plan – far more than a few notes to accompany a slide deck could ever provide.