I know much of the discussion around sprint is focused on multiplayer, but I really noticed how it affected combat in Campaign and Firefight as well. The sprint ability drains the tension from many combat scenarios by enabling us to make easy escapes from mistakes, and neuters what were once serious threats. Hammer Chieftains and Hunters used to be formidable, especially in Halo 3 and ODST, because of how they could close ranks; they required smart tactics and maneuvering to keep them at bay we had enemies who could out run us. In Reach, Hammer Chieftains and Hunters are almost comical because we can simply run away from them (or fly away, even). Its one of the mistakes made in the sandbox design, boosting our abilities without rethinking the enemy.
When we're given added maneuverability options, and the enemy does not have ways to counter them, combat gets too easy and encounters can lack tension. I'd like to see a good clip restored to our base movement speed, but if we get added abilities like sprint or a jump pack, enemies need ways to counter us without resorting to being cheap. Otherwise what are intended to be formidable opponents are going to be a cake walk again.
I'm in the camp that is absolutely, completely, 100% against Sprint -- but I don't always have it in my head as to why, and your post reminded me. The bread and butter of the Halo campaigns are the encounters, and if there is an element that is introduced that ruins or reduces the enjoyment factor of certain encounters, it needs to be removed. Full stop.
If you have to work around a new element, or if you have to develop a counter to it, it probably shouldnt be in the game in the first place.
I somewhat disagree. Axing sprint completely takes away an option the player has. That's been one of the things I love about Halo; is that the player has so many ways to tackle an encounter whether it be multiplayer or against AI. Personally I'd love to see the customization options that Reach Firefight has implemented into campaign. I'd love to go The Ark only fighting Hunters and vehicles. I'm all for the return of sprint, jetpack, and everything else; but for the love of god don't ram it down my throat like Reach did.