While it’s against our policy to share exact formulas (in order to keep guilds from gaming the system), we do want to be sure and clarify these mechanics to the best of our ability for those guilds who are concerned about how guild leveling actually works.
The best of their ability is very poor. “It is a sound system involving a lot of math” does not tell us anything. “The system takes into account the characters’ level, and is balanced in a way to allow guilds of all sizes to level up at comparable (but not necessarily equal) rates.” This statement also translates to “we’re not going to tell you anything useful.” The best I can infer from the post is that completely inactive characters do not count against you, but mules and slightly active alts do. So Casualties of WAR was completely right about severely limiting alts, until we get a conflicting statement down the road.
The guild leveling system was obviously not part of any open testing. No one is allowed to know how it works, so we cannot tell if it is working properly. That is one way to keep the bug count down.
Conveniently, it does not matter in the long run. Every guild that sticks with the game will hit max level (or near enough) in several months. And what are the odds that anyone will quit because it took too long to get a guild emblem on their cloaks? Everyone will stick the guild leveling system in the “ignore” box soon and not think about it until someone looks at the code in two years.