Ok, Like other games, before I do this, i'm give you an example.
Let's say you're in a good game right? And someone leaves on your team, it just ruins the experiance. I'd like to se someone join in and replace him, any empty slots could very well be joinable, i see this in alot of games.
But there is a downside. If the player joins, the only get about half the game. Honestly i think it would be a Ok idea. Maybe 343 can fix it a little. Makes Halo more friendly, especialy when your whole team quits! Anyone have their opinons? PLease add on.