how come- even though it’s a prequel- halo reach’s stuff is more updated. like theres more guns . theres an extra species of covenant. and there’s armor abilities
I would imagine, story and canon-wise, that this is because Reach is the industrial and military powerhouse of the UNSC. It develops some of the most powerful weaponry, ships, and general technology that you can imagine. I imagine that Armor abilities are pretty new and rare, so I do not think that places that you visited in the original Halo trilogy will have had full access to them. Now that Halo 4 is set five years after Halo 3, the UNSC will have been given time to recover, so we can expect to see them more widely dispersed among soldiers.
Gameplay-wise, video games need some innovation to continue to capture the interest of gamers. Bungie will have wanted to introduce some new gameplay mechanics. Instead of rehashing equipment from Halo 3, they will have wanted to take an evolution upon them, and turn them into the Armour abilities of Halo: Reach. I hope that was a satisfactory explanation.
thanks