In the beta if you can remember there was a elite vs Sparten playlist both played by humans I didn’t like it in the beta but i wish it was in the the real game Halo:Reach so if 343 FIX the halo reach playlist and put it back in then i would play also most of the halo reach population
Firefight Versus? you can find it in your Custom Games Gametypes section 
Unfortunately no playlist for it as of yet
and I think it’s only 2v2 now.
If I remember right there’s way too much lag with any more players and all those NPC’s.