Joining mid-game in Matchmaking?

I do like the Halo Matchmaking, but if there was one change I would make, I would set matchmaking to where players can join mid-game to fill slots quitters made, like MW3. Any other ideas you believe in?
EDIT: Lol, so apparently they ARE adding mid-game joining.

Have you been living under a rock?
They have said that you can join mid-game already

all i hope is that the matches will be longer

if TS stays ~15 minutes long, 80% of the time, you will be joining into a finished game

I do not live under a rock, but I did not here of this.