There has been a lot of discussion about the join in progress system introduced in Halo 4. I feel that it is a good idea (which many may disagree with), but its current implementation has a fatal flaw - it allows games to start with uneven teams. This fact, in my opinion, is the single greatest problem with JIP.
The JIP was designed to rebalance games after people leave. In theory this is great, since I experienced many a game in Reach where one or more people left making the game very unfair or boring, depending on which team you were on. However, because games can start unevenly in Halo 4, the JIP system is having to fill games that people have left from, and it has to fill slots in games that that started with unbalanced teams to begin with!
This creates even more games that the system has fill up, more games that people leave because they are not inclined, in general, to stay in, which means that there are even more slots to fill up!
Now that there is no penalty (or a less harsh penalty, I’m not sure) for leaving games, people are more likely to leave a game now than in Reach, so making games start evenly is not going to completely solve the problem: people will still be put into games mid match. However, I have to think that it will help, and I would think that it would reduce the frequency with which people are put into the middle of games.
So please, 343, change it so games start with even teams.