I've seen this done before (yes, Blender as a power-point replacement).
Using Camera Switching
Blender can use timeline markers to switch cameras.
This means you can jump between markers to switch slides.
You can have 3d text in each view, and animate the visibility if you rather they don't display in every slide.
This also has the advantage that you can press Play and watch the full presentation.
See: How do I cycle through the camera views?
Using Scenes & Screens
You can configure each screen in blender to be a slide in a presentation.
Ctrl + Left/Right to switch.
Each screen can point to a different scene (or the same scene with different cameras in each viewport).
You can also make use of background sets (the ability for many scenes to share one common scene as a background). - see scene buttons.
Using background sets means you can have a common scene for the detail, and other scenes can overlay text or any elements you don't want to enable all the time.
Using Scenes & Outliner
This just means adding one scene per slide, and using the outliner to change between them, The small disadvantage here is you need to have the outliner open, so you can't switch slides fullscreen.
With this method you can still use background set-scenes, and its rather quick to setup. If you wanted to you could always add a key binding or addon to switch scenes without using the outliner.
- Enable 3D View -> Display (Panel) -> Only Render
This stops cursor, manipulator and other info widgets from drawing, so you can focus on the content
- You may find 3D View Full screen useful to play the presentation,
its setup to minimize distractions.
- If you want to get rid of the header too - this can be toggled with Alt+F10.
- This Python command will cycle to the next scene:
from bpy import context
context.screen.scene = bpy.data.scenes[(bpy.data.scenes[:].index(context.screen.scene) + 1) % len(bpy.data.scenes)]