Apparently the Gliding ability is needed to make it to the entrance of this Guild Hall claiming mission, which is something you unlock after a couple of new story missions (if I'm even understanding that right, I haven't touched the new zones or content yet myself). I want to apologize for not looking into this thoroughly enough beforehand to be able to put out a bulletin of what would be necessary for all players that wanted to participate. I was only able to get in at all myself based on the "Teleport to Friend" functionality and we tried to scramble and get as many in as possible with these limits. If you were not able to come due to this, I empathize as I had no idea myself. I made an incorrect assumption that since so many guilds of massively varying sizes would want to do this ASAP, it wouldn't have any progression requirements (or at least any that couldn't be bypassed if some of the guild had them, to be able to bring others through).
If you couldn't attend our claiming event tonight due to this, I encourage you to join us if you can make it tomorrow at 3:00PM EST to claim the other Hall, Gilded Hollow, for our secondary overflow guild GAFO. I have looked into it and it says that for this one you need:
Exalted Mastery Lvl 1
Access to the Auric Basin map.
Again, I'm sorry about this turn of events and hopefully everything from this point forward will be a lot more straightfoward. It is confirmed, at least, that actually accessing the Guild Hall once we have it claimed has no prerequisites and anyone will be able to come explore it.