Hmmm....those are some good ideas guys. I think the best course of action is to have 1 of each type of guild. a Battle Guild, a Production Guild, a Small-Medium Sized guild, and a PK guild(for those who are a bit more sinister). And of course, you can be guildless if you so desire! Of course there are other guilds that exsist, but none of our characters will be in them, though we can certainly interact with them as needed.
I think I'd like this RP to have an element of sand-box, but still have plots and subplots to augment the overall story. As Clocktower mentioned, I want this rp to be semi-sand box so people don't feel like they have to wait for the next plot device to do anything. There will be major plots, but as long as its smart and clever, people can create subplots as the story goes on. It doesn't all have to be planned out.
And yes, in this expanded version of Log Horizon, all the classes from the other servers are available. I may actually add some custom classes and subclasses. Though, we will probably stick to the basics for now.