Headers should be sortable by presentation viewers. This would incredibly improve the functionality of presentations and cut-down on the need for creating duplicate presentation pages simply to apply a filter.
AND...if filters are applied to a presentation page, they should be included, so it's clear to the viewer what their looking at (e.g. what is and isn't being included).
I think this would be a great feature and add a lot of value in terms of how we use presentations. Thanks!