I still don't understand your PoV here. You are saying in its default form, speedboost is basically useless and so is damage boost, therefore combining them (well kinda... since there is more detail to Haste than just combining Halo's versions of damage boost and speed boost) would also be useless? That doesn't make sense.
It makes perfect sense. 0 + 0 = 0
its a new thing to halo so you have no idea really and neither do I.
YOU might have no idea, but I do.
BUT we do have the example from Doom where its far from useless.
Doom isn't Halo.
You're also saying that the only way to make either one of those existing mechanics useful would be to stack them multiple times when in reality there is a middle ground there.
No, there isn't.
Not to mention i would already argue that damage boost is useful but the damage increase per bullet aspect totally breaks power weapons. Turning the sniper into Norfang and giving rockets a nuclear sized kill zone is not the same as letting a player shoot them a little faster. Thats an execution problem that a Haste type powerup fixes. And speedboost would already be useful if everybody didn't have a speedboost button on their controller. Its useless because sprint is a thing, so lets blame the right thing here. Its not Speedboost's fault that the ass-cancer that is sprint exists.
Speed boost being useless has nothing to do with sprint.
Again, there is no harm adding a bunch of shit to a halo game like this. If it ends up sucking... just don't put it on maps. its not changing a core, ever present mechanic. its basically a variable that designers can add to their maps that doesn't fuck with the actual design of said map. If it works, use it, if not, don't.
You don't build a tight, rock-solid sandbox like Halo CE by just throwing a bunch of shit in the kitchen sink. That's how Halo 4 and Halo 5 were handled, and they're both terrible. That's not a coincidence. Do I have to link Hardy Lebel's blog again?
If someone really wants to create a powerup like this, let them do it on their own with a custom powerup. All the trait modifications are already available, except for RoF which can easily be added.
Haste isn’t comparable to damage boost though. Damage boost reduces the number of shots it takes to kill someone. This means you can be less accurate, and still get kills. Haste allows you to shoot faster- but the number of shots to kill doesn’t change- so you still need to have good aim.
The end result is the same; damage output increases. In a powerful sandbox like Halo 1, that turns the player into a walking nuke. Nobody wants to play against that.