The main popular people that did gw2 livestreams you wont be able to join their group, but we should be able to get lower exposure. I say this because TotalBiscuit did 2 live streams for gw2 and a few of the popular machinima personalities also did live streams. Those people are kind of out of reach unless someone knows them personally. But live streaming isnt too difficult, there is some trial and error when you first start out, but its not rocket science. Xsplit will eventually be pay to use though, so just keep that in mind. twitch tv servers are also in america and europe, so asian countries may have some issues doing 720p+ streams, but you cant do those streams until you are a partner with twitch anyway, so no worries there.
Basically 2 screens make it so you can easily play the game and enjoy the graphics while paying attention to users that are watching the live stream. The most popular live stream personalities will respond to questions and a few other things while they are playing the game. Audience interaction is important to gaining viewers when you initially start out. Of course if you are like totalbiscuit and have 4k viewers as soon as you start your stream you don't have to worry because people will come watch you anyway. Day[9] is the same way. he has like 4k+ viewers as soon as he starts streams.