could 343 add a co-op matchmaking to cea?

I know that they used the original engine for CEA, but couldn’t they add to the engine so that there is a co-op matchmaking?

If they did add a co-op matchmaking to CEA, it wouldn’t like the one in Halo: Reach. It’ll have these features:

-There is no veto nor voting system. The game automatically chooses a campaign level.
-In the matchmaking lobby, the player could only choose a difficulty, and the game finds a match aimed towards that difficulty. So if the player chooses the heroic difficulty, the game finds a partner within that difficulty.
-No skulls will be added.

So could 343 add a co-op matchmaking during the development of this game? If they could, why didn’t they?

It might worth it, but for all the lagging.