I recently saw Division 4 being created in order to combat the large amount of participants in contest, and it got me thinking: why stop there? How about we made a new division for every rating, where only users with that rating can take it!
Think about it: ITS GENIUS. There won't be too many contestants on any contest, and there will be MANY more problems in the problemset! Codeforces would become a haven for upsolving!
Furthermore, it would prevent LGMs from alting, because division 1500 would be the only division with alts. Amazing idea.
To calculate rating, it's simple. If you are in the upper half of the contestants in some contest, then your rating increases by 1. Otherwise, it decreases by 1! Brilliant!