A good example is this incredible optical illusion by Akiyoshi Kitaoka, a Professor of Psychology at Ritsumeikan University, Japan, which reveals removing objects from your peripheral vision tricks the brain into thinking it is moving slower than it is.
Halo was never "too slow."
One reason some say classic Halo is "too slow" is because they don't understand that FOV greatly impacts our perception of speed.
Halo 2 & Halo 3 had a FOV of around 70 on Xbox. A low FOV makes us see things as being slower than they actually are.
In…
This optical illusion is another good example. (Works best on desktop.)
Cover up the center of the image with your hand. The dots around it will appear to speed up. Cover up the edges, and the dots will appear to have slowed down.