I'm not try to bait out an argument here, I'm just a little confused about what point you are making here. The stability of IM is shaky right now, the lower tier teams break up and won't play because they are in over their head and the upper teams break up for a number of different reasons. In the case of most teams the reasons result from personality conflicts which are compounded by losing. If you narrow the skill level to more equal levels in a division, positive team building results would occur. A team that enters open together, makes it to im, and so on and so forth, has a better chance of NOT breaking up than a team of im players that just play with each other because there are no better options. Personality conflicts happen in all games, the biggest phenomena in tf2 is the mixing up of players every season. I'm just simply suggesting that a four division league might help lessen the extent of that problem.
In the end though, you are the captain of the ship, you make the tough decisions. It is futile for me to argue, so I will stop and understand the choice you make. I hope your announcement doesn't disappoint
and fyi, I do understand that the lack of numbers in tf2 really does limit the way you can design a league. It was more of a hypothetical solution than a practical one.