Personally, I'm going to need a very strong argument to get me to lean towards this being a good idea. I don't mean to be a stick in the mud here but I'm not seeing any guilds with enough active players to warrant this right now. I will discuss it in depth with Uadjet and we can brainstorm and I'm willing to take suggestions here or any other way you wish to
contact me for discussion or ideas to persuade me.
Currently, I am looking at the bigger picture of this. 5 "interested" guilds. 1 has one member who's logged in 2018...in March. The other four? Either has one active member only or 1 person that's even logged on in the past 30 days. (July). Only one guild even has 5 people who have logged on in 2018. The rest are 1-4 members who have logged on in 2018 (Some of whom don't even have 10 hours of gameplay or have not logged back on in over 6 months).
So there you have my thoughts on why I'm against it. But again do not lose heart, I can be persuaded easily to push this forward if given a good enough reason.
Guildhouses are overrated anyways. They are hardly used, other than to drop tons of items that the server has to load each time it crashes or is restarted, and several guildhouses are so full of junk and items that they not only lag horribly but most times you have to relog when entering or exiting because you unleashed the famous guildhouse bug.