Yeah, but these are easy to get around. Say if by a miracle there is ranks, they'll just do the same thing they did when there were ranks, keep shooting you until you're 1 shot so the enemy can kill you easily.
The suicides all they need to do is suicide a few times, then kill one enemy, suicide a few times, kill an enemy, suicide a few times etc.
And for the AFK problem, all they'll need to do is attach an elastic band onto their controller so their spartan continuously runs forward.
We definitely need a miracle... I don't know what will happen for me with halo 4 if there are no ranks.