A feature I am looking for from a presentation software

It should be easy to group a list of slide and give them a section overview.

Each slide should have six navigation buttons in Play mode:

• Home
• End
• Next
• Previous
• Back to Section Overview
• Next Section

The side navigation panel in the Design mode should show the outline structure.
Use the Section Header slide to "group" other sides and allow collapse and expand.

I found an old article "A Flexible Alternative to PowerPoint" on the net.  It said the same thing:

One of the disadvantages cited by Tufte and others is that PowerPoint tends to confine the speaker to a single pre-set path, discouraging spontaneity and diminishing flexibility in response to the audience's interests.

Browsers can not only emulate much of PowerPoint, they can also do things that PowerPoint does not....A table-of-contents window can be on screen at all times, allowing you to jump spontaneously to different topics.