The Timeless Isle will have a world boss specifically for players who have their legendary cloak -- you need it to reach him. The Timeless Isle itself is not quest-based, but focused more on exploration, discovery, and semi-random events. There may be additional world bosses or things like them mixed in there.
Edit: The Monday Morning Blues made me forgetful -- the August Celestials will be world bosses on the Timeless Isle. You don't kill them, only defeat them in a trial of combat.
Why is it always harder to find raiders during the summer, when school is out and no one is obligated to study, turn in homework, or meet academic deadlines?
In summer, the last thing I'm interested in is needing to abide by a raiding schedule. I, and others, would much rather have the freedom to go outside and enjoy the sun whenever it please me, rather than whenever my schedule allows. WoW becomes a secondary thing -- what I do when I'm done with everything else. In winter, there isn't much else to do it all, and that's when WoW becomes leisure activity #1.
In a followup comment you also said: "I can understand going outside, but it's beyond my experience to want to go outside and play at 7 pm central on a Wednesday."
It may be beyond yours, but it isn't beyond mine. It's still light out at 7 p.m. In summer, it isn't full dark until 9 p.m. or later. What stops people with no obligations from being out after dark, anyway? The world doesn't snap-freeze, nor are there vampires crawling from the grave.
Do you have any WoW Ships / OTPs?
Kinelory and Quae. No doubt about it. If I need to reach harder, I'm going to echo the comments with Jaina and Vareesa.
I wanted to plug Wrathion and Anduin in here as well, but with how murky their ages are, thinking about it creeps me out a little.
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