Hi, as many people do, I have a personal Guild with a bunch of storage open.
While I know we will ‘merge’ Guilds across worlds, I’m wondering what happens to the items and in particular the unbound exotics that are ‘Soulbound on Use’. Do we need to remove them before the patch, in the case these won’t be unlockable for any of the new Collection categories on my account?
I have somewhat of an ‘Armory’ going for a unique exotic shelf of sorts.. up to 70-ish exotics at the mo, which I’d rather not lose 
Cheers
“There’s no lag but what we make.” – biofrog
You shouldn’t see any change, if it’s just your personal guild.
The guild vault from the world that had the highest number of slots will become your global guild vault. If your guild had the same number of slots on multiple worlds, it’ll pick the one with the most items. However, the items from other worlds’ banks will not be lost—instead, their contents will be put into extra slots, which will only be available to withdraw from and will disappear once empty.
https://www.guildwars2.com/en/news/continued-improvements-to-the-megaserver-system/
~The Storyteller – Elementalist – Jade Quarry~
Yep, I’m just secretly hoping something there isn’t an unknown change, like all Soulbound on Use items in the guild bank aren’t available for unlocking achievements 
“There’s no lag but what we make.” – biofrog