Hijacking vehicles isnt halo
Duel wielding isn't halo
Equipment isnt halo
Grappling hooks isnt halo.
See a trend?
The thing is all of those don't force the maps or the campaign to be designed around those mechanics, they are there to spice the gameplay, to experience the campaign or the multiplayer in a different way depending on the item, vehicler or weapon that the map has; dual-wielding sucks? then you can just spawn two-handed weapons or make them more rare to appear, hijacking doesn't feel cool? then disable the option in the gamemode options or just don't spawn vehicles on the map or learn to drive equipment seems OP? if you can't nerf it just don't put them on the map and that's it.
With grappling hook (sprint and clamber) it's different because they will have to design the maps around that thing, imagine traying to play Asylum or Pinnacle with that thing, the map would feel "small" due to the new mechanic, so they will have to make the map bigger to compensate for that, like they did in Halo 5's Heretic, making the normal traversal around the map slower, forcing you to use the grappling hook if you want to go top speed. There are many videos that show how the maps suffer because of spartan abilities, Halo 3's and 5's traversal in Heretic are the best example when it comes to explaining this issue.
