What tells you that we won't also get it on the 7th? For Aes we didn't even get an announcement, it just popped up in the maintenance notes.
Because 3% DPS is stupid easy to get in a 4 party run. I'm on sub 23k attack and I get over 3% no problem with other +15 weapon players. The reason why less than 3% DPS = 1 core is because it's a way to prevent players from AFKing in raids because KR has had this issue with it and the players are pretty damn mad about that. Personally no one really has an issue with it because getting over 3% DPS is easy If you actually play the game. Because statistically speaking from KR's end of things (I don't say NA because DevCAT doesn't manage NA data or servers). Players that actually play get over 3% DPS even in 8 man parties. In 4 man parties it's even easier.
Edit: Forgot to add this but if anything it's harder to get ALL cores since you have to get top DPS for that I think.