The changes to the guild system that BlizzCon announced last weekend will arrive when Cataclysm does. Several folks are talking about the possibilies already.
As far as I can tell the Solo MMO Player's realm has only a few raiding guilds but a lot that are either leveling guilds (where a Level 80 character walks the newer characters through instances) or run only for the benefit of the officers (join our guild and pay into the guild bank and we'll ask you to run an instance but only if we get the loot). This may or may not make a difference in the lack of raiding, but it'll certainly change things somehow.
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