Most all of the threads in question are self contained and are actually a sub-forum themselves.
The College Football thread for instance, is a place where ALL college football gets discussed. There aren't multiple threads for each team, today's game, the BCS, etc.
Same with the NFL thread, the MLB thread and that "soccer thread"
This is also true of the MRville Games. Each game is self contained within the thread
All of the community has done a good job of keeping everything within its own thread in these cases. The fact they are at the top is just a testament to their popularity among those who frequent them.
Yes, perhaps you could put the 6 sports threads in a sub-forum, or the 2 MRville game threads in sub-forum, but why? So you could find the "Am I being a jerk" thread more easily? Or the "Help me catch a cheating spouse" thread?
I believe the Community Forum is defined by the community far more than by the site structure. People post threads that are important to them and frequent them.