User blog comment:RA2/Rankdown Series 4 Discussion & Questions/@comment-4700688-20180503135851/@comment-1011118-20180503140904

The rationale is that Pic-n-Mix here would make for 8 rounds where the Doom Dial could be used, and with 9 players that would be a real avalanche. I got the sense that a lot of people wanted in on Series 4, so my priority was having the max number of slots.