The Area51 'vetting' process is an unnecessary barrier to creating new and interesting 'exchanges' (I guess it makes sense from a cost perspective), and they need to adjust the user experience for the non-geeky universe.
Don't forget, all these Stack Exchange sites are thought up by the community, but then deployed and paid for by Stack Exchange. They don't want hundreds of "ghost towns" around the web, they want to only create a new site if they think there's a reasonable chance it will grow into a site as vibrant as Stack Overflow. That's what the whole process is about. Time will tell if it's a good process.
But think about the real costs. Assuming that they have a nice scalable multi-tenant design, a ghost town is not going to have a lot of content or users, which means only a small hit on their database. Yes, tons of ghost towns add up to significant costs, but that can be easily fixed with some simple rules around inactivity over a set period of time.
Wayne Gretzky famously said "You miss 100% of the shots you never take." StackExchange is taking a 'rifle' approach. More power to them. My own personal opinion is that a 'shotgun' approach could result in more successful sites than the one they're taking. Just my 2 cents.
I think this diagram sums it up great: http://blog.stackoverflow.com/wp-content/uploads/se2-venn-di...
I'm talking about a shotgun approach while going free.
When you have an empty site and someone sees the last question was weeks or months ago they just browse away. Helping getting the community over that initial hurdle is important.