I say it's all up to you. Although the goals may be similar to other guilds, the backstory is probably different, though most of all, the members. I find that what makes a guild in any game are the members. If your guild has a great background but annoying, unfriendly members, there is no point in maintaining it. On the other hand, if you have a bad story for it, but awesome members, then I say it more than compensates.
In another MMORPG I play, I was in a guild who's members where very friendly, and helpful. After a while I became good friends with the guild leader, and had a few good occasions to show that I would help him. Now, unfortunately, things have changed. A rather large guild with over 200 members created a branch for us, and those of us who still play switched to that branch. Now things are very different... At least I'm still friends with the guild leader.