I just want to say i have made a guild and invited friends but they cant join because they didnt have nough guild slots and to be quite honest 5 just isnt enough lol maybe its time gw2 updates this? because it isnt the first time i have heard of this topic <3
on that note, having a new guild hall requires upgrades such as silverwaste shovels sometimes 50-100 at a time per upgrade, these are rare drops in Silverwastes; they should be easier to come by as a high demand req. guild hall upgrade material
anyways thats all lol 
have a good day everyone = P