One of my favorite things about classic Halo, and why I hate the way advanced movement has been implemented in the newer games, is that you can take any possible route on the map while dueling someone. This freedom to navigate and fight simultaneously is essential in a game that is paced like Halo, where high skill players almost never miss and winning a 2v1 is nearly impossible unless you can break sightlines without taking free damage. If you can’t put shots off on them, they have more safety to play aggressive with their shields, while also having the incentive to take you out before your shield or teammates return. If you can put shots on them, they have to balance the pressure their aggression against the risk of getting outshot, increasing the impact of everyone’s skill in these situations.
In addition, this kind of freedom also rewards having the map knowledge and positioning awareness to be able to make jumps without looking, and while focused on aiming (or grenade placement). At present this is only possible where crouch jumping can clear a ledge, which turns many routes into deathtraps that you want to avoid in almost all cases, lest you get caught out with only the clamber as a “viable” escape. Similarly, trying to use these routes aggressively is usually a bad gamble, giving any enemies in LoS the time to react and put shots off on you as a prelude to a fight.
Giving players the ability to at least look and shoot while clambering would open these routes up more, making the maps overall more vibrant as these spaces become usable paths, allowing players to spread out more and stop crowding into the 1/2 routes that aren’t elaborate suicide. And it’s not like crouch jumps wouldn’t still be worthwhile just by way of being faster and not having the extra animation time to lock your movement.
And come on, you can’t tell me that my spartan can leap 2m+ vertical but can’t do a one handed pull up facing backwards.