Originally Posted by
clevin
Allow me to jump in for a sec... what I think you're missing is that more casual guilds attract different people than heroic guilds. Heroic guilds have a rep on their servers and by and large the people who seriously apply to them know what they're getting into with things like standby, DKP, etc. They will put up with that because the reward is being part of a server first guild or at least a high end, heroic guild. That might mean prestige to a player or just that they're part of a team playing at a high level.
In contrast, a more laid back guild attracts people who aren't as into that stuff and so might not take to being rotated in and out in the same manner. They just want to show up a couple of nights a week and raid with decent players, not worry about standby, DKP, who need what loot from which boss, etc. Also, trying to rotate adds complexity, overhead and potential drama which the RL and officers need to deal with.
Now, imagine you're a casual 10 man raid. You want to progress some, but you'll be satisfied if you clear normals in the current tier. You can define a rotation scheme, publicize the rules, get people to buy in, deal with some people who don't like it and leave by recruiting, etc.... OR you can decide you're not all that invested in whatever prestige comes with clearing normals, say "fuck it" and raid flex. If 13 people want to raid, great, you raid with 13. If the next night only 11 show, no problem. Same if 15 show. Awesome, let's all raid. None of the overhead, none of the drama. Hell, since loot is personal like LFR there's not even a need for DKP schemes.
Flex will kill normal mode guilds. Some normal mode guilds will step it up and become the entry tier of heroic raids... but the guilds who pretty much only raid normals? In 6.x those will be a tiny minority and most organized non-heroic raids will be flex.