Increased Base Speed

Is just a fancy way to say “Halo without Sprint”.
It’s not an alternative, it’s just removing sprint.

Why?

Imagine if 343i declared they would just up base speed to 120%.
They would then design all of the maps for that, therefore making the maps the same proportional size.
People’s reticle wouldn’t move as fast, which would give a little bit of an illusion that people are faster, but that could be fixed with higher aim speed (which is already an option)
The only things that would actually move at a slower pace, and creating the illusion of speed, would be the literal dropping of weapons, speed of grenades, and possibly vehicles (whose speed would also be upped anyways), and bullets (but most are insta-hits at anything shorter than really long distance).

So, in the end, there’d be the same problem that Anti-Sprint people complain about. The Illusion of Speed
Admittedly, this illusion would be more convincing because our brains/eyes wouldn’t react and absorb information proportionally faster, making the speed seem real.
But’s it all proportional.
Let’s say you have a 10 ft. hall. It takes a person, without Sprint, 4 seconds to cross it. Now, let’s say they increased the speed to 120%.
That means the hall would now have to be 12 ft to not “break” the game as many would say, which still takes 4 seconds to get across.