Okey, there seems to be some misunderstanding as to if inactives slow the guild leveling down, i don't actually know if that has been the case of if its a one of them urban myths but here is a claim where the myth gets busted.
Q. My fellow guild officers and I are having a ‘discussion’ about whether or not we should alts in the guild. How does guild leveling work, exactly? Would having a bunch of extra inactive characters cause our guild to level more slowly than if we were all active?
A. No, having inactive characters in your guild roster won’t slow down your guild advancement. A guild gains experience and ranks through the actions of its members. Anytime members earn experience and/or renown the guild earns experience as well. So having a battalion of inactive alts is not a detriment to your guild’s ability to level.
Noone needs inactive players in the guild but alts are a great addition, first they actually give the guild experience secondly you might find out that there is a keep warband up and log on to your main just by reading the guild chat.
The link to the statement is here
Hope this clears it up and if there is another fresher statement that denies this feel free to tell me and the rest.