As a Tottenham supporter from 1968 naturally Klinsmann would be quite a coup for Team USA. Whether he would be better than Arena at coaching the talent level we have is by no means clear.
If Klinsi did lead Germany to the finals then why would he want to bother taking the USA job when realistically making the QF is about as much as one can reasonably expect?
The reason is that Klinsmann lives now in California, and has an American wife, and I believe wants to eventually become a US Citizen.
I think what a guy like Klinsmann has over Arena, is an understanding of precisely how the game is played in Europe and what it takes to win there. This isn't the NCAA or the MLS.
And also much less pressure coaching the US, than Germany, where if you not only don't win, but win decisively, you are open to constant criticism from the German press.