In my opinion, this is a horrible idea. Especially after playing Guild Wars 2, it seems that the only people that benefits the most out of this are the much larger guilds that have been already established. In the video OMFGcata said Zenimax had invited leaders of some of the biggest guilds around the world. I feel that this is only favoring them while neglecting smaller or new groups that want to grow.
I'm currently in a guild with friends that I've met in other games such as Aion and Lineage II. A group that has stuck together for several years. We're currently all playing GW2, but have decided to postpone the recruiting process until we have a better idea of the game mechanics before actually "leading" in a direction. Once we were ready to recruit more members, it seemed that players would only join our guild but then represent a much larger, more well-known guild after we've helped him or her. This feels no different than a person joining a guild to take advantage of an offer and leaving it, only to ask for help later on by joining again. Of course the well known guilds will have much more people in them and more people available to go into a dungeon with. I'm sure many may like this system as it allows them to roam freely in and our of groups, but I don't believe the concept of a guild is fully reinforced in a system like this. Besides, isn't that what a party is for?
I hope TESO doesn't have this horrible system on release. Building up on a community is one of the biggest reason I play mmos. I am strongly against it and would be a major turn off.