The new changes for raiding...
It comes down between choosing 10 or 25man, with 25mans not having better gear, only less. restokin has a nice view about it, and she really delves into the what it will do with the people managing guilds. I have been there.
In 2007, I was the-one-that-did-almost-everything. My RL needed that, an excuse to be alone. And I managed, until my RL changed. Running a guild is a lot of work, or rather, running a 25-raiding guild (although social) who raids 6 days a week. That means you have to have around 45-50 members (social guild) with people attending about half the raids, supplemented with some that did a lot more.
Now, if you have never did this, it's hard to imagine. XII had around 50 members, of which 1 was the GM, and 8 others where officers. The GM was more for PR, and to sometimes make the descision to continue, but was not doing much for the raiding-part. 5 officers where mostly there for inviting, and relaying messages to the other 3, who did most of the work, recruiting, forming raids, guildbank stuff, website... that stuff.
That means 40 other people where mostly just showing up for raids. And like in most guilds, not all where that clever. There have been enough times where I should have kicked people, but to keep the peace, and the raids going, I didn't. But it comes down to the fact that 3-5 people did a lot for the others, which wasn't always seen. It also meant, that sometimes you just didn't know someone good enough.
And everyone was there for the purplez of course, now if 10s are going to drop the same as 25s, I must concur with restokin, who would be crazy enough to do 25s (unless they drop 1.5 times the loot maybe). You can keep the really nice an good people, and ditch the rest. And the fact that the guild wouldn't that be that big, you would know each other better, less turn-over, and better results probably.
There are some concerns though. 10mans favor hybrids. Why? Simple. If one person can do multiple roles, the number of people in the guild can be lower. So one day, you are healer, and the next day tank. So 10-guilds will not have many pure dps-specs, not more then 2, else if one of the tanks/healers is not there, no run. Or you could do it with 16 people in the guild, where a lot of the time 4 people are benched, and it depends on the number of days.
If your 10man would raid 6 days/week, a guild of around 20, with more pure-dps would be possible. But if you only raid 3 days (like most guilds)., 12-14 should be enough, but you need to have a lot of hybrids.
I probably could let loose a lot of statistics, but, luckily, I am not raiding at the moment, so it will not affect me.... maybe.