I think the real problem here is not so much as where the circle is located, but whether participants can be gathered timely. I am not against one in Luna simply because I do not think it will matter.
I play on GL and sometimes you will be able to get others to join a circle within 5 minutes. Other times, you might get two others and will stand there waiting for others for almost an hour. The shard population makes depending on others to use this skill not worthwhile. Whenever I am on, and I see someone ask in General Chat, I will go to WBB and participate, but I really don't see a lot of requests when I am on. Admittedly, however, it is very disruptive to participate, and often times I will stand there with just the caller for more than 15 minutes. That is a long time to not be able to do anything else.
There really should be an alternate means of getting this accomplished. Maybe another quest, with the award being NPC's will form a circle, with the level being based on quest accomplishment?
FWIW, people are not lying or lazy when they complain about not being able to get a circle. We don't always play during the same time, and some times are harder than others. I will admit that the lazy accusation might be legitimate when it comes to patience --- one should be prepared to wait at least 15 minutes before calling it a failure.