Go look up the vod of blizzcon where Ion talks about it.
NVM, here you go. A forum thread you might like (or not, a lot goes on in it). With the vod and a timestamp for the Ion’s comments (1:05:24 fyi)
Definitely about people not getting loot due to loot rules.
The problem was never good guilds that did not take advantage of their members. Bad guilds are generally bad in all ways. But even good guilds can run through quite a few people before finding a good fit. All those people put in time and effort and end up with…well hopefully new friends and some good times. But…no gearing progress to help them as they prospect in yet another guild trying to find the one they do fit in.