It will be between 9th and 21st it don't take long to do it i would even bet that w1 would just be that world under a new name with the updated versions so all on same stuff.
just cause they proberey picked already i suggest some they will never pick.
Leftovers
Lies win
Lots of cash
Lineup
Looters
Lazy
Loading
Little toe
Last stand
Let the dust settle
Login
Less is more
Loud egos
sorry in advance
Personally I would lets say double the Character Prem nuggets in worlds where they don't have sets or only get some decent sets from quests/events that is timed so when you complete them it goes then you have to do it again. So players have to do it again to get the slight edge and keeps up...
It has been done before they released a world without the current event so it don't have to wait for this one to finish. Also they have to give enough time for avg players to get to a level where they can do Halloween quest which is usually 2 weeks I may be wrong.