Just an idea for replays of the campaign, With fractures being a thing why not bring that in as a gameplay mechanic we already have it in a way with difficulty how about having it with other things Fractured settings would change the gameplay in some way similar to skulls but much farther reaching. While a skull effects stats and what spawns a fracture effects the world as a whole.
info: expand the armory of the enemy and your allies adding new weapons like the type-27 carbine, flamethrowers, halo 5 erra BR, an MA5B, and other weapons. each weapon has its own toggle so be smart and think of what weapons you want in a run. the more weapons the more options but the more likely there are to be enemies with them. Beam rifles bring beam rifle jackals so watch out.
causes the UNSC survivors to be a greater part of the story, talking to chief and the weapon and bringing in reinforcements at key points including the tank run at the end. The pilot is no longer the only pelican left introduces another pelican crew who will appear after the AA guns are brought down. Also returns marines ability to drive and in co-op allows players other then the host to have marines in their vehicles (though that should be a default feature)
Brings in several halo wars 2 era banished units, including the grenadier, bruit shot soldiers, goliaths, and several vehicles like the AA boat that is the ravager and artillery that is the shroud.
Puts several UNSC vehicles on the map which can be unlocked in the FOB, from teh wolverine and cougar to the Gauss hog and Swords hog (hog with needler turret and energy shields)
Requires down but not out, adds ODSTs, Sanghelli soldiers, engineers, and even UNSC jackals/skirmishers to the UNSC ranks engineers will boost your shields when near an FoB and repair vehicles. though they will only be found at FoBs.
Host is chief the rest are blue team, each has a unique set of 4 abilities though all have the grapple hook and shield booster, Linda for example has cloak, fred has armor lock, Kelly has a jetpack. all their abilities are different.
Chief is found dead, the pilot is saved by a group of spartan IVs who where captured. different start mission and you play your MP spartan.
Wonder what halo is like with out shields and with medkits instead. Replaces your shield with a health bar, improved shields is replaced with a CE medkit that regenerates your health out of combat but at a slower rate then your shields. good luck.