Things Halo 5 Multiplayer must have

Dual Wields
Return of old weapons such as Plasma Rifle and SMG
Drive able air craft such as Pelicans and Phantoms
Fire Fight
Option to Fight against Flood in Fire Fight
Driving Scarab and Elephant for BTB
Blood Gulch
Option to play as an Elite during Certain game Types
Larger Maps For large Vehicles
Forge items that can be used on any map as well as items Exclusive to different maps

I really want the Incendiary grenades from Halo 3 back, and the flamethrower. I like burning things.

Also, Grizzlies.

If 343 returned every thing they removed that would be good but i want large vehicles that the entire team can be using at same time

Locusts, Locusts, Revenants, Choppers, Locusts and Locusts.

> I really want the Incendiary grenades from Halo 3 back, and the flamethrower. I like burning things.

How about a Brute Shot that fires Incendiary Grenades?

> > I really want the Incendiary grenades from Halo 3 back, and the flamethrower. I like burning things.
>
> How about a Brute Shot that fires Incendiary Grenades?

That would be kind of OP. The incendiary grenade from Halo 3 was good because it had terrible range and explosive damage, but the fire damage was devastating. If it was fired from a brute shot, it would have high range, fire, and explosive damage.
However, I like your idea. Maybe there can be a grenade launcher (like from Reach) that can be picked up on the map and can fire grenades from your inventory, while also nerfing the grenades in certain aspects like blast radius and overall damage in exchange for increased impact damage and range.

The CE Plasma Rifle and the ODST SMG would be much appreciated.

And the CE Flamethrower.

And the CE Fuel Rod Gun.

Fully-playable Elites.

I think fully playable Elites and a new species that is along the lines of a forerunner A.I./robot that the librarian left behind for the humans to use possibly named the Promethean Pawn or something like that.

The story behind the Elites could be that the Arbiter Alliance sent Elites to be pared with the spartan IVs, and for the Pawns they could have been found on a forerunner shield world or something like that.

And another thing is I think that the plasma rifle could be brought back because the storm rifle is more like the plasma repeater just no way to cool it down manually.