Can you imagine taking down the Scarab in Halo 2/3, Kraken in Halo 5, tank v tank fights, or fighting through massive structures if you had the grapple hook? You would see everything obsolete since you can scale layers, swing yourself within structures, and grapple vehicles without much pain. It neglects direct puzzle-solving or traditional linear pathways that open after a sequence is done.
For example, Halo 3’s mission 4, when you take an elevator to jump onto a scarab. You can bypass all that by just swinging yourself onto the scarab itself. How often will you find yourself doing that in each scenario? Sure you can create some structures becoming non-grappling. But then you defeat their point of the grapplehook being a sandbox weapon. There would probably be even more kill barriers. Now imagine that in many more scenarios in past Halo games.
I remember the only mission Infinite where you ride a tank to the House of Reckoning on Heroic/legendary, once you lose that tank, you actually were pinned through mass amounts of infantry. The only challenge that Infinite actually manifests is just through sheer amounts of Banished forces. In my eyes, I see it as lazy campaign gameplay. Giving you the tools to solve your own problems at spawn, drop as many enemies as they can then call it a day. I think it’s also why Hunters became such bullet hassles to take down without equipment use.
There is never going to be another massive combat unit situation that is challenging or linear missions that don’t support your equipment. Equipments just solve everything for you. Now I’m not against the equipment, just it should really not be something you spawn with.