Personally, I do not think there will be any effect on the pool or if there will be, it will be very, very minimal. Think of a set of items/candidates/whatever rated between 0 - 400. As long as you want to pick 400 items out of these, it doesn't matter in which order you shuffle them (bring 0 to top, demote 400 at 0's position etc).
The point I am trying to prove here is, after June 6 changes, people who are already in the pool will be bumped up to top positions, but the Total number of candidates in the pool will remain the same. The cut-off score is defined by the number of candidates CIC wants to pick out of the pool. So, it doesn't matter if an applicant from 390 is bumped up to 415, he will be picked up early for sure, but at the same time, the total number of candidates or the pool size in simple words will be reduced equally, reducing the CRS as it is expected to reduce.