Universal language...there's no reason why people speak different languages anymore, they only create barriers now. In our newly technologically connected world, our languages we speak should not be getting in our way anymore...
That being said, I think there is something to be said for diversity of culture, and perhaps better more fluid translation services are the true solution.
The fact that the question is still open is why (in my opinion) the thought experiment is so interesting.
Plus there's the bonus of the Esperanto travel network, where people all over the world allow others who speak Esperanto to stay with them for free/cheap.
Definitely recommend it anyway - and good idea.
How about a software solution for translation that works perfectly?
While a tool to instantly translate a conversation while two people speak would be amazing, it would have the same effect as having a universal language in my opinion.