What 343 needs is
Transport vehicles: Like the falcon and the passenger Warthog that seated at least 5 people as passengers in the campaign but that wasn't an option in multiplayer.
Elites: They need to bring them back to multiplayer with full customization like in halo 3 and possibly like an elite firefight or elite ops that would be very interesting.
Firefight: Mostly everyone agrees that need to bring back Firefight for halo 5 but with different modes like a flood type or a covenant type depending on how the Arbiter's Covenant are doing in this game.
Skulls: I loved finding the skulls in halo 3 in was a challenge for me to find them, they should be like they were in halo 3 when you would get a certain number you get a pieace of armor like the Hayabusa armor, plus bring Hayabusa back to with the katana on your back.
U.N.S.C. flying vehicle: you guys need to bring in at least one of the flying vehicles like the hornet or falcon or some new type of vehicle.
Customization: I'm talking more armor customization, Armor effects, Visor colors etc. all that good stuff.
The Arbiter: If hes not in halo 5 then i dont know what i'll do but bring him in this.
Flood: Maybe bring them in the campaign for a short time, But maybe a flood firefight type game mode.
Duel Wielding: Bring back duel wielding, i loved duel wielding smgs and f**king **** up but i needs to come back.
Forge: Ah yes forge mode, Well it needs a big forge map like it was in halo reach but different biomes like one part would be Snow, another would be a Desert Part, and another like a normal sunny part, Or just like a Weather Changer for the whole map but yeah.
I know theirs alot more that needs to be added but this is what definatley be added in halo 5 maybe not all of this but some parts. Keep doing us good 343, Thanks for all of this.