Whilst the ‘members leaving midweek issue’ clearly screws a guild over, it is kinda the same for everyone. We had this issue last week. I hope we don’t this week.
Whilst it feels unfair, it is fairly unfair, in that any guild can get the same issue, so the playing field still feels level. Better guild communication and team spirit may help, to lessen people leaving and manage better the process when they do.
As such I don’t see this as a problem that really needs fixing. Same happens in sport, when players get injured or sold, and so on. And worse in real life. Just have to manage, and maybe miss out on a few in game free goodies. Worse things happen, and there are worse bugs or imbalances or just plain new features I’d rather the devs worked on.