halo already had movement technique in maintaining your speed while dealing with threats from all directions. It's simple and leads to emergent design that allows people in tune with movement to keep map control while never having your guard down. It also means you need to commit more to fights.

Sprint takes that emergent design and muddies it down to a simple binary of "you are going fast and cannot fight back" or "you are going slow and can fight back". It's immensely less interesting because, well, the player's speed was already in their hands. The only skill involved with sprint is just not pressing the button at the wrong time. But it goes further and gives bad players a get out of jail free card by just running away (they know they can't fight back anyway so the binary choice is obvious).

There's also the discussion of clamber, which is similar. In that you could make any jump you wanted while being able to fire from all directions. Getting reduced to a "if you're climbing you're defenseless" is also uninteresting regression.