Just I would like to leave my own opinion about the mappool, I hope this could be helpful for further events
Basically, the score system overall has been changed a lot, it means in this scoring system the accuracy have been more important than pure combo, so I think the maps which are pretty hard to get droplets so it'll make more accuracy drop but easy to FC compared with the other maps will have potential to be added (e.g :
https://osu.ppy.sh/p/beatmap?b=87764&m=2 Megpoid GUMI & Megurine Luka - Speed [Speed] (inb4 this map has been picked in CWC 2014 so nothing to worry about it))
Hidden mappool shouldn't be harder than NM mappool, but there are some opinions from players that they think playing maps in Hidden mappool with No mod is still harder than playing No mod maps, yes, they were overbalanced. I also agree that hidden mappool was overbalanced, so I wanna see some lenient difficulty of hidden mappool
Also I agree that low AR(8↓) Hidden map should be existed for strategic mappick, but it shouldn't be a mainstream because low AR hidden is completely an anti-meta. As everyone saw CWC 2016 Finals' Hidden mappool has total 3 of AR8 Hidden pick, it wasn't really a nice idea imo. Hidden mod's difficulty isn't only depended on AR, I think the map's characteristic and pattern usages are more important. Even it's pretty high AR compared with low stuffs there are still many of complicated hidden picks with difficult patterns, e.g :
https://osu.ppy.sh/p/beatmap?b=686374&m=2 Camellia - dreamless wanderer [Crystal's Overdose] . So I think just using 1 slot for low AR hidden for every rounds shall be the best way to make ideal structure of mappool
For HardRock mappool, I highly recommend to add 1 map with kinda 'memorization' map which needs more memorization to keep combo, this will make unexpected result of the rounds, and also will force players practice it to handle the worst condition. Also they could use their ban cards on it so it'll make the ban phase more interesting
Others are pretty clean, it's sad that I couldn't join the mappool selector for this year but personally I'm really happy to see the better quality of mappool, especially we could see the converts on every rounds again! Sorry for my bad english but I've tried my best to write this to see better things of this (probably) the best tourney. Thank you