We are planning to introduce a division system to AtCoder in the near future.
Here are our current plans (but this is tentative, we may change it based on your feedback):
The division cutoff is 2000. I think this is about the same as CF's 1900.
We'll hold div2 contests (called ABC) every week. Usually, 100 minutes and 5 tasks: 100, 200, 300, 400-500, 600-700. Rated for 0-2000.
Sometimes we'll hold div1 contests. There are two types of div1 contest: AGC and ARC. The first two tasks are shared with div2.
ARC: Usually 100 minutes and 4 tasks: 400-500, 600-700, 800-900, 1000-1200. Rated for 2000-2800.
AGC: Similar to current AGC. Rated for 2000-inf.
One major problem is that even strong people have to spend a few matches in Div2. Two "red performance" is good enough to reach Div1. Is it fine?
For example, it says that a gray coder solves a 200-point problem with probability 63%. Note that we use "estimated rating" instead of actual rating for this table (i.e., we don't subtract 1200 from newcomer's rating).
Please post here if you have some opinion about it.